I'm trying to diagnose why my car is running so rich - it's kicking out black smoke...and I'm pretty much out of ideas. I have a 3.4l pr that has sprint headers. I've ported out the intake manifold a little bit to match the gasket lines. There are roller tip rockers and PO said there's a crane cam in there, but I don't know the exact one.
My running rich problem came after I put in new injectors (they're the 17lb BMW ones). Previously I was getting detonation with even moderate amounts of load. The new injectors solved that and I had gobs more power for a couple days. Then I went out and all of a sudden the car was bogging down and bucking, and barely keeping an idle.
I've tried electrically disconnecting the MAP sensor and when I do, the car seems to run just fine - no smoke. I've also checked that vacuum line and it sticks to my finger. In the readings below, it seems like it's functioning normal right? (4.75v at engine off, 1.88v at engine idle) Other sensors seem to be fine too (coolant, TPS goes through the whole range smoothly with throttle input). O-2 sensor I installed today. Note the MAP errors were from me disconnecting it.
So the coolant temperature is being reported as less than 114°F? Is this supposed to be a warmed up engine?
The engine is not fully warmed up in those pics. I had run it earlier to full temp (and got the code 45 - rich). Just didn't want to cloud up the garage again, but I can if it's helpful.
The A/F mixture will be influenced by both the MAT and coolant temperatures (a colder engine requires a richer mixture), so it's important to know what readings are being sent to the ECU when the engine is fully warmed up.
I also like to occasionally check the MAT and coolant temperatures first thing in the morning after the engine has sat all night, to make sure these two readings are very similar. The engine isn't running for this test. If the readings of the cold engine aren't close, at least one of the temperature sensors is probably faulty.
The A/F mixture will be influenced by both the MAT and coolant temperatures (a colder engine requires a richer mixture), so it's important to know what readings are being sent to the ECU when the engine is fully warmed up.
I also like to occasionally check the MAT and coolant temperatures first thing in the morning after the engine has sat all night, to make sure these two readings are very similar. The engine isn't running for this test. If the readings of the cold engine aren't close, at least one of the temperature sensors is probably faulty.
183 on the coolant, 77 on the MAT. Might not have fully warmed up, but this was after a few minutes. I think the temp sensors are doing okay. As it has sat in the sun, the MAT is now up to 90 and the coolant down to 110.
Are those BMW injectors high impedance? They must be high impedance for the engine to fuel properly. Are they new or used? There are three types of fuel injectors, Pintle, Ball and Seat and Disc. The OEM Fiero ECM is set up to control the Bosch Pintle style. If you are running the correct injectors then test for leakage and check out the sensors as suggested in this post.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
Are those BMW injectors high impedance? They must be high impedance for the engine to fuel properly. Are they new or used? There are three types of fuel injectors, Pintle, Ball and Seat and Disc. The OEM Fiero ECM is set up to control the Bosch Pintle style. and check out the sensors as suggested in this post.
40 psi when charged. Goes down to 20 over about 30 seconds and then takes about 5 mins to get to 0. I pulled the fuel rail and charged it several times and can see that none of the injectors are actually leaking. I presume the leak is at the fuel pump which shouldn't be causing a rich condition.
Anything else I should check while I have the fuel rail out?
[This message has been edited by tnkgnr (edited 03-24-2021).]
[Quote tnkgnr: I got a new (never used) set of these type - which should be the pintle version (0280150415): https://www.injectorplanet....ts/bosch- End quote]
Those are the correct upgraded injectors for the 3.4. They have the correct impedence, the correct pulse width, the correct flow at 16.76 lb/hr at stock Fiero fuel pressure of 43.5 psi. and they are pintle (4) injectors.
EDIT: Due to the problems some are having with the 0280150415 EV1 injectors, I am suggesting that you consider the 0280150941 Bosch injectors, instead. They have worked well for me for 50,000 miles, but the moment I upgraded to the EV1 injectors, I experienced all kinds of problems.
I would do an ohm check on the Coolant Temperature Sensor. Best way is to remove it and let it come to ambient house temperature. Do an ohm test on it's terminals and compare to this chart. http://www.gafiero.org/bbs/...=641.msg4644#msg4644
I have had a CTS fail on me while stopped at a traffic light. Looked like a diesel, but it never set a code. A scan showed -28 F. I unplugged it to go purchase a replacement and then it set a trouble code. But it ran much better. I would also check the IAT on the air filter canister. Most of ours have never been replaced. You can use the same GM chart above.
[This message has been edited by fierofool (edited 04-15-2021).]
Originally posted by fierofool: I would do an ohm check on the Coolant Temperature Sensor. Best way is to remove it and let it come to ambient house temperature. Do an ohm test on it's terminals and compare to this chart. http://www.gafiero.org/bbs/...=641.msg4644#msg4644
I have had a CTS fail on me while stopped at a traffic light. Looked like a diesel, but it never set a code. A scan showed -28 F. I unplugged it to go purchase a replacement and then it set a trouble code. But it ran much better. I would also check the IAT on the air filter canister. Most of ours have never been replaced. You can use the same GM chart above.
Thank you for confirming the right injectors (I believe I purchased them from reading one of your previous posts)
The tunerpro scan is showing somewhat accurate temperature readings for the MAT and the CTS. For example, the outside temp is 57 degrees now, and my car in the garage is reading 61 on the coolant and 68 on the MAT.
Today, we pulled the upper manifold and replaced the plastic vacuum lines with Rodney's stainless lines. The new injectors went in at the same time. When we were finished, the car started right up and ran great. It was initially a little rich until it got up to temp. Not running rich at operating temperature and idle.
We pressure tested the regulator once the fuel system was buttoned up and on the original 87 pump, it primed at 44 psi. We failed to test at idle.
I did have some problems on the way home. It had a stumble at acceleration, and when coming to a stop, it wanted to idle at 2000 for a moment, then it would drop to its normal 1100. If the stop was too long, the idle would drop almost to the point of stalling out, then recover back to 1100. The car didn't seem to have the power in the lower rpm, but when I had a chance to step down on acceleration, it was its old self.
I think the stumbling and erratic idle is due to having disconnected the TPS and IAC and not caused by the injectors. The car's back under wraps for the severe weather. We'll see what's going on Monday when the weather clears.
If my injectors are running correctly and yours are flooding out, the problem can't be with the injectors.
Today, we pulled the upper manifold and replaced the plastic vacuum lines with Rodney's stainless lines. The new injectors went in at the same time. When we were finished, the car started right up and ran great. It was initially a little rich until it got up to temp. Not running rich at operating temperature and idle.
We pressure tested the regulator once the fuel system was buttoned up and on the original 87 pump, it primed at 44 psi. We failed to test at idle.
I did have some problems on the way home. It had a stumble at acceleration, and when coming to a stop, it wanted to idle at 2000 for a moment, then it would drop to its normal 1100. If the stop was too long, the idle would drop almost to the point of stalling out, then recover back to 1100. The car didn't seem to have the power in the lower rpm, but when I had a chance to step down on acceleration, it was its old self.
I think the stumbling and erratic idle is due to having disconnected the TPS and IAC and not caused by the injectors. The car's back under wraps for the severe weather. We'll see what's going on Monday when the weather clears.
If my injectors are running correctly and yours are flooding out, the problem can't be with the injectors.
Mine has the stumbling with low amounts of acceleration, but performs great at near or full throttle. Idles around 1000 sitting in the garage. If I take it out on the road, when I bring it back it will barely idle near 600 and stall out to where you need to give it throttle to keep it going. My TPS and IAC are connected and giving readings.
If the above is from your 3.4, has it ever ran correctly with the injectors we're both using?
I have had these sitting on the shelf for a while. Just put them in Saturday. We also changed out the vacuum lines for stainless lines. I don't know if the tubing from the MAP to the fuel pressure regulator is the same size internally. I might go back and put the plastic line back to see. If the stainless line is too small, it won't pull vacuum as well. If all else fails, I might go back to the old injectors, too. They are for a Ford V6 and are only rated at 14.1 lb/hr, which is a 15# injector. Same as stock Fiero.
There is a caveat regarding the injectors I took out. I purchased injectors that were properly sized for the 3.4. I gave them to my engine installer. Apparently, they were traded out for the 14# injectors that I just pulled out. No wonder I was running lean. If I put them back in, I'll likely bump up the pressure to get the flow required if I don't resolve the stumbling issue.
Put the old injectors back in. Idles fine. Erratic/stumbling on little to moderate acceleration. Feels less powerful on full acceleration (also remember these injectors I thought were clogged)
I also double-checked the timing after full warmup.
I think I'll check to see if the CAT is clogging things up.
Could there be something mechanical that's wrong or I'm missing?
I talked with a guy in Cincinnatti yesterday who also swapped to the upgraded injectors. He also had the stumbling issue. Like me, he had done nothing other than swap out injectors, but it was a new 3.4 install. Nothing was done to the Fiero stuff that bolted on, including the TPS. That's exactly what happened to me. We removed my upper plenum and carefully laid it aside.
He tested voltage on the TPS, bumped up the TPS stop and the problem went away. Idles at 1100 and doesn't drop out to 500 or stall out.
I looked at some of the specs for the old injectors, and there's a slight difference in impedance. The old injectors are 14.4 ohms and the new ones are 15.9 ohms. I'm advised by some electronics-savvy folks that that will make little difference in their operation.
I would suggest taking a look at the TPS and maybe adjusting the stop upward a bit.
As far as a clogged cat, I don't have one but the guy in Cincinnatti does, as you apparently have, yet all 3 of us are having issues. Don't think that's the problem.
I would suggest taking a look at the TPS and maybe adjusting the stop upward a bit.
By this, I take it that you mean to adjust it so that it thinks there's a slight amount of acceleration going on (pushing the actual lever down a bit). How much are we talking? 1/8 inch? More?
Overall, I'm curious - are these injectors considered experimental for our 3.4l purposes or have many used them with no problems?
Went to get a chip burned by Sinister Performance thinking (hoping) my issues could be resolved through the ECM. After sending the logs, he indicated the O-2 was trying to pull 85% off the fuel map, so something must be seriously wrong if it's still running rich. Indicated my problems could potentially come from incorrect valve lash, incorrect length pushrods, cam lobes wiped, or defective lifters.
I did a compression test on the 1/3/5 bank - 1 and 3 were at 135psi, 5 was at 115. I put oil in #5 through the spark plug hole and tested again - was still at 115, so assume valve issue?
I opened up the valve covers. On the 1/3/5 bank I could spin all the push rods but one with my fingers, so I'll be tightening that up. None look bent.
Anything else I should do while I've got it broken down a bit? I also bought a scope and could see that the valves appear to be crudded up a bit.
Rockers:
Bit of a chunk out of the piston - but still holds pressure:
[This message has been edited by tnkgnr (edited 04-14-2021).]
...my problems could potentially come from incorrect valve lash, incorrect length pushrods, cam lobes wiped, or defective lifters.
I did a compression test on the 1/3/5 bank - 1 and 3 were at 135psi, 5 was at 115. I put oil in #5 through the spark plug hole and tested again - was still at 115, so assume valve issue?
I opened up the valve covers. On the 1/3/5 bank I could spin all the push rods but one with my fingers, so I'll be tightening that up. None look bent.
Perhaps I'm misunderstanding what you're saying, but it's not making total sense to me. How exactly did you do your valve lash in the first place?
tnkgnr, I have gone back to my old injectors which were used in the Ford 4.2 liter V6 engine. It did away with the rich burn, but didn't solve the stumbling issue. I was still getting TPS and MAP codes. I replaced the TPS with a new one and still had the MAP code. Replaced the nearly new MAP with a used one and that code went away, but I still had the stumbling. I probed the TPS and adjusted idle voltage to 0.51 volts by bending the paddle on the TPS. It still has a slight stumble, but I think that may be due to my having loosened and readjusted the TPS stop that's on the throttle body. Idle is good after adjusting voltage, right at 1100 and it doesn't try to stall out on idle.
The odd thing is that when we did the conversion, we didn't touch the TPS or MAP and those were the issues once putting it back together. Everything was handled very carefully, so I don't believe we disturbed anything.
Yesterday I was replacing the MAP harness clip and when I started up, the car would hardly run. It was so rich that I had to keep revving the engine to keep it running. I went back to check the harness end to be sure I had fully reset the pins when I repinned it. I found the green plastic piece that came on the harness plug wasn't allowing the harness to fully engage the MAP. I removed it and everything was good. Maybe you should check your MAP harness pins to be sure they're fully inserted into the harness plug.
I am strongly considering editing my original article and recommending the Ford Bosch 4.2 injectors over the upgraded EV1 injectors. At least they work with less problems.
Perhaps I'm misunderstanding what you're saying, but it's not making total sense to me. How exactly did you do your valve lash in the first place?
I've never adjusted the valve lash. This is the first time I've checked it out since I've owned the car. I'm learning as I go along here, but my understanding is that when adjusting lash you should tighten until you can't spin the pushrods, and then tighten one more turn (+- .5 turn depending who you ask).
tnkgnr, I have gone back to my old injectors which were used in the Ford 4.2 liter V6 engine. It did away with the rich burn, but didn't solve the stumbling issue. I was still getting TPS and MAP codes. I replaced the TPS with a new one and still had the MAP code. Replaced the nearly new MAP with a used one and that code went away, but I still had the stumbling. I probed the TPS and adjusted idle voltage to 0.51 volts by bending the paddle on the TPS. It still has a slight stumble, but I think that may be due to my having loosened and readjusted the TPS stop that's on the throttle body. Idle is good after adjusting voltage, right at 1100 and it doesn't try to stall out on idle.
The odd thing is that when we did the conversion, we didn't touch the TPS or MAP and those were the issues once putting it back together. Everything was handled very carefully, so I don't believe we disturbed anything.
Yesterday I was replacing the MAP harness clip and when I started up, the car would hardly run. It was so rich that I had to keep revving the engine to keep it running. I went back to check the harness end to be sure I had fully reset the pins when I repinned it. I found the green plastic piece that came on the harness plug wasn't allowing the harness to fully engage the MAP. I removed it and everything was good. Maybe you should check your MAP harness pins to be sure they're fully inserted into the harness plug.
I am strongly considering editing my original article and recommending the Ford Bosch 4.2 injectors over the upgraded EV1 injectors. At least they work with less problems.
Seems there are a bit of issues if you're getting TPS and MAP codes. I get neither and all sensors are showing good accurate data. Have you tried reverting to original 2.8 injectors to get a baseline? I would have tried that but haven't come across a cheap set.
I've never adjusted the valve lash. This is the first time I've checked it out since I've owned the car. I'm learning as I go along here, but my understanding is that when adjusting lash you should tighten until you can't spin the pushrods, and then tighten one more turn (+- .5 turn depending who you ask).
Are you aware that depending on which rockers are being adjusted, the crankshaft/camshaft needs to be rotated to a particular position?
I feel that using the method of "spinning" the push rods creates a way-too-wide margin of error. My take on adjusting valve lash is Here.
[This message has been edited by Patrick (edited 04-15-2021).]
Seems there are a bit of issues if you're getting TPS and MAP codes. I get neither and all sensors are showing good accurate data. Have you tried reverting to original 2.8 injectors to get a baseline? I would have tried that but haven't come across a cheap set.
I changed back to the 0280150941 Bosch injectors used by Ford. Bosch rates them at 14.1 lb/hr at 43.5 psi. By all injector calculators, that is undersized for the 3.4 engine, but they are working well, except for a scanner reading showing the BLM is maxed at 156 at wide open throttle. Still, in 50,000 miles, I haven't suffered any engine damage. These are the injectors and their specs. https://www.injectorplanet....cts/bosch-0280150941
The 0280150415 flow ratings are all over the map, according to various Bosch flow rate charts. Anywhere from 14 lb/hr up to 22 lb/hr at 43.5 psi. Several listings show these injectors are for boosted engines. Still, it's puzzling why some of us are having no problems while some have had the issues you and I are having. This is where I bought mine, and the specs. https://www.injectorplanet....cts/bosch-0280150415
One application chart I found showed that the 415 injectors were for a 4.2 liter Ford engine rated at more than 200 HP. But the 4.2 engine doesn't show up on a search for a listing of Ford engines.
I found a new set of 2.8 injectors on Rock Auto. They're made by Standard Motor Products. Part Number FJ9-P. They were about $65 for a set of 6.
The 0280150415 flow ratings are all over the map, according to various Bosch flow rate charts. Anywhere from 14 lb/hr up to 22 lb/hr at 43.5 psi. Several listings show these injectors are for boosted engines. Still, it's puzzling why some of us are having no problems while some have had the issues you and I are having. This is where I bought mine, and the specs. https://www.injectorplanet....cts/bosch-0280150415
The ones I bought said they were for 1990s BMW vehicles - consistent with the M50 and M52 motors from your link. The horsepower and torque range 148-240hp and 140-240lb torque seems right where we'd need it. Wonder if their compression ratio (10-11 to 1 vs. our 8.9) has anything to do with it.
I'll try one more time after I correct the valve lash and button it back up, but I did purchase the original set from Rock Auto you mentioned as a backup.
I had time to do a little searching today and this is what I found for top feed Bosch injectors.
0280150415 injectors 16# = 16.76#/hr @ 3 bar (43.5 psi) compares on InjectorPlanet and InjectorRx websites. 0280150715 injectors 15# = 15.4#/hr @ 3 bar 0280150778 injectors 17# = 18.2#/hr @ 3 bar
The 0280150941 (Ford FOSE-B5A) injectors I switched back to are rated 14#/hr at 3 bar according to the InjectorRx chart and InjectorPlanet chart. They were recommended and provided by Fuel Injector Connection. That actual flow is 14.1#/hr
Put the stock 15# injectors in. Also figured I'd try the coin trick in the fuel pressure regulator. Put a quarter on top of the spring. My fuel pressure is ~53psi on initial key-on. If the fuel injector calculators are correct, this should be pretty good for the 3.4l application (80% duty cycle for 160HP).
No longer runs rich. Accelerates great. No codes.
Still have a problem with stumbling at low-load/cruising with slight throttle.
My fuel pressure is fine. I went back with the old injectors that were running just great. Still have the stumble on acceleration. Though we didn't touch it, the timing was off, had to replace the MAP and TPS, and I keep getting a rich exhaust code. The only thing different from what it was originally is that I installed Rodney Dickman's stainless steel lines. My theory on the stumble is that the fuel pressure vacuum line is smaller than the original plastic line, and the vacuum doesn't pull as quickly, taking a moment for the larger fuel pressure regulator nipple and chamber to achieve a full vacuum. I'm thinking about pulling the upper intake again and replacing the fuel pressure line with the original plastic line.
I'm going to take my EV1 injectors to Fuel Injector Connection and have them flow tested to see what they are actually flowing due to all the varying information.
