1988 Formula manual. V6 2.8 upgraded to 3.1l. Not experienced mechanic but am learning slowly so please explain like I'm 5.
Started losing power a few months back and I realized the 3 front cylinders were not powered and the Inj2 fuse was blown. After swapping the fuse it worked find for a while then blew again. I did a lot of forum research at that time but never found the cause (I'm starting this new thread because the other one was so old - thanks to all who helped back then). Mainly because I swapped out the fuse again and the problem didn't reoccur. I drove it 2-3 times a week on short runs for a couple of months. Then the fuse blew again and now I can't get it out of the driveway without blowing a new fuse.
The fuel injectors were replaced when the previous owner switched to a 3.1 but I haven't opened it up to visually inspect them...I was hoping to avoid that. Based on forum post help when I originally was looking at this issue, I was told the EGR Solenoid shared the same fuse. So today I unplugged the wire harness from the Solenoid, assuming that would eliminate the possibility of that causing the fuse issue. Still has the problem.
My question is a) was unplugging the wire harness from the side of the EGR Solenoid enough to eliminate it as a suspect? I didn't remove the entire thing but I didn't see any other wires going into it. b) what should be my next step? Checking the fuel injectors? I'm not sure what I'd be visually looking for on those or I'm not sure how I'd isolate the broken one unless I just replace them all.
Unplugging the EGR solenoid should take it out of the equation. Period. Nothing else that I know of is powered off of that circuit/fuse. Maybe (If you can reach) try unplugging the front injectors one at a time. Or if you can get an ohm meter to them, measure the individual injectors. It's possible that one of them has shorted. They should measure around 12-14 ohms. But anything "close" should be okay. You can also unplug the flat connector that feeds ALL the injectors. It'll be located kind of near the MAP sensor and the thermostat housing. If the fuse doesn't blow after you disconnect that connector, it kind of eliminates everything between the fuse block and that connector. Points to a shorted injector or injector harness. I believe the pink wires (there should be two of them) supply 12V to the injectors all the time. The ECM fires the injectors by switching ground.
[This message has been edited by Raydar (edited 09-08-2024).]
I'm starting this new thread because the other one was so old...
Three months ago is "so old"? You must be very young.
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Originally posted by danahart:
So today I unplugged the wire harness from the Solenoid, assuming that would eliminate the possibility of that causing the fuse issue. Still has the problem.
For a short time, it (unplugging the EGR solenoid) should be okay. Make sure to listen though for any indications of engine ping due to the EGR system not being functional. Also keep in mind that if there's a short in the EGR solenoid harness (rather than the solenoid itself), that the INJ fuse could still blow again.
[This message has been edited by Patrick (edited 09-08-2024).]
So... if you unplug everything fed by that fuse (like the EGR valve, and then the injector harness), and the fuse still blows, then the trouble will almost have to be in the harness, somewhere. This is based upon the premise that the engine doesn't have to be running for the fuse to blow. (Obviously it won't run with all the injectors disconnected at the flat connector.)
Maybe not so young but unfamiliar with this forum and how it treats past posts. The old thread also included a code error that has never reoccurred so I wanted to start with the fresh data that didn't include that old issue. However, I guess that could be related .... but it has never reoccurred. I don't have any dash warnings. I appreciate you help with the old and this new post.
How would I go about testing to see if the harness itself is the issue? Should I cut it off and rewire it back again if all stays the same? Is there an easier way to test it?
Thanks and that makes sense. Can I unplug the injector harness without taking off the manifold? Is the connector accessible or does the manifold have to come off?
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Originally posted by Raydar:
So... if you unplug everything fed by that fuse (like the EGR valve, and then the injector harness), and the fuse still blows, then the trouble will almost have to be in the harness, somewhere. This is based upon the premise that the engine doesn't have to be running for the fuse to blow. (Obviously it won't run with all the injectors disconnected at the flat connector.)
It doesn't seem to happen if the engine isn't running. I just tried turning the key but not cranking a bunch of times leaving it for a while as well and couldn't get it to blow. The times I was driving when it blew, I was always hard accelerating up a hill. It has blown in my driveway so I don't think it ONLY happens on high rpm or maybe that is just when I notice it because the sound/power loss is more noticeable. I'll try to do more testing to see if I can nail down a pattern.
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Originally posted by Patrick:
It would help to know the answer to this. Does the fuse blow with the ignition key turned to Run without the engine running?
It doesn't seem to happen if the engine isn't running. I just tried turning the key but not cranking a bunch of times leaving it for a while as well and couldn't get it to blow. The times I was driving when it blew, I was always hard accelerating up a hill. It has blown in my driveway so I don't think it ONLY happens on high rpm or maybe that is just when I notice it because the sound/power loss is more noticeable. I'll try to do more testing to see if I can nail down a pattern.
sounds like the injector is having an intermittent fault. you can check it's power wire to ground to see which injector is shorted. I would actually unplug your cold start Injector if its still equipped since most 3.1 engines do have larger injectors and can easily have faulty injector ontop of them drawing just a little more power. but DO NOT replace the fuse with a higher rating whatever you do.
Thanks and that makes sense. Can I unplug the injector harness without taking off the manifold? Is the connector accessible or does the manifold have to come off?
It is quite accessible, just looking at the top of the engine - usually between the upper intake and the thermostat cap. No need to take off any manifold/mechanical parts, unless you want to unplug the connectors from the individual injectors. It's usually a flat connector about 1.75-2" square. One half of the connector goes to the main harness, and the other goes to a handful of wires that disappear under the upper intake and connect to the injectors. I said "usually", because some of the 88s had a different connector that was more of a cube shape, but performed exactly the same function. It will also be in about the same place.
Thanks. I found it without issue and disconnected it. I tried cranking the engine a bunch of times and couldn't get the fuse to blow. I plugged it back in and it blew with just a few 3000rpm low revs. So I guess that rules out the wiring on the battery side of that connector. My issue must be on the engine side or like carter above said, there is an issue with an injector itself. I was really hoping your idea would find the issue was just in a wire outside. I guess I need to keep looking.
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Originally posted by Raydar:
It is quite accessible, just looking at the top of the engine - usually between the upper intake and the thermostat cap. No need to take off any manifold/mechanical parts, unless you want to unplug the connectors from the individual injectors. It's usually a flat connector about 1.75-2" square. One half of the connector goes to the main harness, and the other goes to a handful of wires that disappear under the upper intake and connect to the injectors. I said "usually", because some of the 88s had a different connector that was more of a cube shape, but performed exactly the same function. It will also be in about the same place.
Ok. I'll try unplugging the cold start injector. I assume to check each injector, you mean to take off the manifold and test each on the injector itself? Why wouldn't I want to use the higher rated fuse? Wouldn't that just likely cause the troublesome injector to fully break, identifying the problem?
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Originally posted by cartercarbaficionado:
sounds like the injector is having an intermittent fault. you can check it's power wire to ground to see which injector is shorted. I would actually unplug your cold start Injector if its still equipped since most 3.1 engines do have larger injectors and can easily have faulty injector ontop of them drawing just a little more power. but DO NOT replace the fuse with a higher rating whatever you do.
Because that's a great way of possibly setting your car on fire.
There's probably a relatively simple way of determining which injector (and/or individual injector cable) has a dead short by probing the injector harness main connector (while it's still attached to all the injectors).
[This message has been edited by Patrick (edited 09-09-2024).]
Because that's a great way of possibly setting your car on fire.
There's probably a relatively simple way of determining which injector (and/or individual injector cable) has a dead short by probing the injector harness main connector (while it's still attached to all the injectors).
see it's not a dead short. it would just blow all the time then. it's acting like a c4 corvettes shellac coated Injectors after someone runs e20 through them. occasionally the metal inside will just touch and short temporarily. honestly the 3000 rpm specifically is quite telling because that's when they start to fully open and pulse faster
Ok. I'll try unplugging the cold start injector. I assume to check each injector, you mean to take off the manifold and test each on the injector itself? Why wouldn't I want to use the higher rated fuse? Wouldn't that just likely cause the troublesome injector to fully break, identifying the problem?
you could but if you are going through the effort to remove the intake then why not get them all tested and take the harness covering off and make sure it's all nice and not kinked or starting to rub through and replace the crappy split loom with better stuff from a local parts store and wrap it in nice tape please do make sure the wiring harness on the side near the firewall (back glass) is able to move freely between the Intake and valve cover and not pinched under the cover.
see it's not a dead short. it would just blow all the time then.
It could be a break in the insulation somewhere in the injector wiring harness, and due to the fact that the wiring harness can move, will only cause a dead short when the exposed wire happens to make direct contact with a "ground" in the engine bay.
None of us has a crystal ball at our disposal to help figure these things out. All we can do is make our best guesses based on our own experiences and the minimal info we're supplied.
Ok. I finally had some time to start working on this problem. I took off the upper manifold so that I could get a look at the wires. Nothing looked pinched and everything looks neat and nicely taped by the previous owner. So now I'm trying to decide if I should pull all of the electrical tape off the wires, inspect, and rewrap each one. Or send out the injectors for testing. Before doing that I thought of an idea - tell me if this is sound.
Currently only 1 of the 2 fuel inj fuses is breaking, the one for the front (passenger) side injectors. If I swap the three injector connectors from the front 3 injectors with the back 3 injectors, that should tell me if it is the wiring or the injectors. If the same fuse is blowing, I know it must be the fuses. If a new fuse blows, I know that it must be wiring since the bad wires are connected to the other side now.
Is that a sound plan? Is there any order to what injector connector goes to each injector? I thought they fired all at once? Thoughts? I may not have enough wire to swap them so, if that is the case, I'll just swap the actual injectors and then see if the problem moves.
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Originally posted by cartercarbaficionado:
you could but if you are going through the effort to remove the intake then why not get them all tested and take the harness covering off and make sure it's all nice and not kinked or starting to rub through and replace the crappy split loom with better stuff from a local parts store and wrap it in nice tape please do make sure the wiring harness on the side near the firewall (back glass) is able to move freely between the Intake and valve cover and not pinched under the cover.
... if you can get an ohm meter to them, measure the individual injectors. It's possible that one of them has shorted. They should measure around 12-14 ohms. But anything "close" should be okay.
No, I had not and thank you for the reminder. I just tested this morning and 5 read 12 Ohms and one only 3. So I guess that guy is the culprit.
New question: Can I just replace 1 injector? Does it matter if it matches the others? I ask because I'm fairly sure the ones in there are not the stock ones. Is it worth sending off the troublesome one for testing/cleaning instead of replacing?
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Originally posted by Patrick:
Did you test the resistance of each injector yet?
[This message has been edited by danahart (edited 09-22-2024).]
Someone with more experience with injectors than I will need to respond, but all I know is that it's optimal for the flow of all six injectors to be very similar. I'm not sure what your best option is... and if you go the route of replacing the whole set, whether or not a 3.1 requires different injectors than a 2.8 engine.
No, I had not and thank you for the reminder. I just tested this morning and 5 read 12 Ohms and one only 3. So I guess that guy is the culprit.
New question: Can I just replace 1 injector? Does it matter if it matches the others? I ask because I'm fairly sure the ones in there are not the stock ones. Is it worth sending off the troublesome one for testing/cleaning instead of replacing?
I think you found your offender. Your replacement really should match the others. What makes you think that they are not original? (Edit - I forgot you were running a 3.1, but most 3.1 swaps I've seen, unless they had other mods, were happy with 2.8 injectors.) Regardless... look at the injector carefully (with a magnifier, even). Bosch injectors, and many others, have a part number cast into the side, near the connector. What is that number? LOTS of web pages still list obsolete injectors. At least you can figure out what you've got. If you can find it, post it up. I'll see what I can find. (I used to do that a lot, looking for injectors that would make my built 3.4 happy.)
[This message has been edited by Raydar (edited 09-22-2024).]
I remember the previous owner told me he replaced the injectors because I recall him saying he liked the multi-spray pattern the ones on it vs the more concentrated stream in the original...or something like that.
Good idea on the numbers. The injector reads "A 8089 17084888". I'm not sure how important the first numbers are but I see some hits on Amazon and Ebay that have the 17084888 part of the number. They look extremely similar but not exact to the ones I have. Do the injectors have that much variance in the flow rate so that I need to match exactly? I could get just one of these and roll with it or maybe it is better to just get 6 remanufactured ones off ebay if those are an ok option and cheap . I also see both reconditioned ones and "new" ones on ebay. I'm leery of cheap "new" parts and they might be chinese junk. I would lean toward a reconditioned old one but would love some input here as I know nothing about fuel injectors.
I think you found your offender. Your replacement really should match the others. What makes you think that they are not original? (Edit - I forgot you were running a 3.1, but most 3.1 swaps I've seen, unless they had other mods, were happy with 2.8 injectors.) Regardless... look at the injector carefully (with a magnifier, even). Bosch injectors, and many others, have a part number cast into the side, near the connector. What is that number? LOTS of web pages still list obsolete injectors. At least you can figure out what you've got. If you can find it, post it up. I'll see what I can find. (I used to do that a lot, looking for injectors that would make my built 3.4 happy.)
[This message has been edited by danahart (edited 09-22-2024).]
I remember the previous owner told me he replaced the injectors because I recall him saying he liked the multi-spray pattern the ones on it vs the more concentrated stream in the original...or something like that.
Good idea on the numbers. The injector reads "A 8089 17084888". I'm not sure how important the first numbers are but I see some hits on Amazon and Ebay that have the 17084888 part of the number. They look extremely similar but not exact to the ones I have. Do the injectors have that much variance in the flow rate so that I need to match exactly? I could get just one of these and roll with it or maybe it is better to just get 6 remanufactured ones off ebay if those are an ok option and cheap . I also see both reconditioned ones and "new" ones on ebay. I'm leery of cheap "new" parts and they might be chinese junk. I would lean toward a reconditioned old one but would love some input here as I know nothing about fuel injectors.
Based upon the seller reviews, I would not buy the matched set. Guy has got fairly crappy ratings, with descriptions of the problems the buyers had. I might be inclined to buy the single injector.
I found a similar one at Fuel Injector Connection (kind of local to me), but the single injector is over $40, and is just showing the application. No part number. Yeah... no.
Thanks for the advice. I'm leery of ordering off Ebay so appreciate the link to the MI injector place. I'd feel better ordering from an injector place even if a bit more. Is there any way to tell that LB my current injectors are? 15lb, 19lb etc? I don't see where it is stated anywhere.
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Originally posted by Raydar:
[QUOTE]Originally posted by danahart:
I remember the previous owner told me he replaced the injectors because I recall him saying he liked the multi-spray pattern the ones on it vs the more concentrated stream in the original...or something like that.
Good idea on the numbers. The injector reads "A 8089 17084888". I'm not sure how important the first numbers are but I see some hits on Amazon and Ebay that have the 17084888 part of the number. They look extremely similar but not exact to the ones I have. Do the injectors have that much variance in the flow rate so that I need to match exactly? I could get just one of these and roll with it or maybe it is better to just get 6 remanufactured ones off ebay if those are an ok option and cheap . I also see both reconditioned ones and "new" ones on ebay. I'm leery of cheap "new" parts and they might be chinese junk. I would lean toward a reconditioned old one but would love some input here as I know nothing about fuel injectors.
Based upon the seller reviews, I would not buy the matched set. Guy has got fairly crappy ratings, with descriptions of the problems the buyers had. I might be inclined to buy the single injector.
I found a similar one at Fuel Injector Connection (kind of local to me), but the single injector is over $40, and is just showing the application. No part number. Yeah... no.
Thanks for the advice. I'm leery of ordering off Ebay so appreciate the link to the MI injector place. I'd feel better ordering from an injector place even if a bit more. Is there any way to tell that LB my current injectors are? 15lb, 19lb etc? I don't see where it is stated anywhere.
They don't publish that info nearly as often as you would expect. I have spent hours looking around and cross-matching part numbers, etc. I would expect 2.8 and 3.1 injectors - and replacements designed for those engines - to be somewhere between 15 and 17 lbs. Leaning toward 15. 17s were considered ideal for 3.4s, but they were difficult to find in the type that we were using. All of yours seem to be the later style. If it runs okay, I would just use the type that you've got. (Sometimes - but not always - changing injector types will cause "hunting idle" issues. But if you're good, just carry on.)
I ordered a reconditioned fuel injector from a injector speciality place. It came and I got it inserted without issue. Got everything back together and the car cranked no problem. I was excited until I drove it and ...something is wrong. The engine sounds rough and is has less power than it should. So I parked it and haven't had time to work on it since. So either that new injector was bad or I messed something up when reassembling. I looking over everything and don't see anything out of place. I took before photos at different steps and all looks the same. So I'm a little frustrated at this point. I guess my plan was to see if it is the injector first by pulling the distributor wires one at a time for a quick sec while the car is idling and see if it changes the idle any. I figure if the injector isn't working, that should be pretty obvious by doing that. Let me know if that is a bad idea.
After that I can only think to pull off the manifold again and recheck all connections, etc to make sure everything is correct. Maybe something came off that I can't see at this point.
I guess my plan was to see if it is the injector first by pulling the distributor wires one at a time for a quick sec while the car is idling and see if it changes the idle any. I figure if the injector isn't working, that should be pretty obvious by doing that. Let me know if that is a bad idea.
Any time a plug wire is "pulled" while the engine is running is a bad idea. It can damage the coil, as those thousands of volts desperately want to go somewhere. It's much better to use a grounded probe at the distributor to kill one plug at a time. Prior to that though, double-check that you simply haven't got the plug wires going to the wrong plugs. It happens more often than you might think.
I'll doublecheck but I wrote the numbers on the plugs in paint pen before I pulled them as I was afraid of that happening. They go in order around I assumed. But I'll doublecheck.
Can you describe what you mean by using a grounded probe to kill one plug at a time?
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Originally posted by Patrick:
Any time a plug wire is "pulled" while the engine is running is a bad idea. It can damage the coil, as those thousands of volts desperately want to go somewhere. It's much better to use a grounded probe at the distributor to kill one plug at a time. Prior to that though, double-check that you simply haven't got the plug wires going to the wrong plugs. It happens more often than you might think.
Can you describe what you mean by using a grounded probe to kill one plug at a time?
High voltage from the coil will seek the easiest path to ground. Normally it's by jumping the gap between the center and ground electrode of the spark plug(s).
One way to supply an easier path for this voltage is to provide a direct path to ground using a pointed metal probe (could perhaps use a small Philips screwdriver) with a wire connected from it to the engine block. With the rubber boots pulled up out of the way of all spark plug wires plugged into the distributor, the pointed metal probe is simply positioned as far in as possible into the edge of each hole in the distributor cap where the spark plug cables are inserted. Even if the probe doesn't actually touch anything metal inside each hole, the voltage will usually be able to jump the gap, as it's easier for the voltage to jump a gap in atmospheric pressure as opposed to the high pressure within the combustion chamber. When the high voltage seeks out ground in this manner, the associated spark plug has been effectively disabled.
I suggest using a metal probe with an insulated handle, but in theory this isn't necessary... as it should be easier for the voltage to travel down the wire to the engine block than through you to ground.
If the probe isn't able to get close enough to allow the high voltage to jump to it from the terminals in the distributor cap, the spark plug cables may need to be pulled up a bit out of the holes in the cap.
I've used this procedure going back to the early 70's with small/big block Chevies.
[This message has been edited by Patrick (edited 10-01-2024).]
You must be very young. 
