3800 Crank No Start (Page 1/2)
AndrewTHG SEP 15, 01:21 PM
So aside from small issues here and there, my Series 3 3800 swap has been running pretty well up until last weekend. Cruising down the street when all of the sudden it lurches, the gauges sort of trip up, but then it picks backs up and drives. Another half mile or so down the road, and all of the sudden it dies. I try clutching in and turning it back over but all it would do is crank, so I pull it into a parking lot. I try and diagnose the problem a bit, look for a loose ground, etc, but it's kind of hard to get under there without a jack so I call a tow truck. As I am waiting a guy comes over and pushes the pintle on the fuel rail Schrader valve and I jump in....starts right up. I leave it running, get home, park it on the road so I can move a car out of my driveway. Go to start it again, no luck. I try the pintle on the fuel rail again, no luck but fuel comes spraying out. I end up having to push it into my garage.

Fast forward to today - I go in, crank a few times, it starts and idles for a few seconds and then dies as the idle comes down to ~1000 RPM. Crank again - same thing. Crank again - same thing. Then, it stops firing again and I am back to the same problem as before. I check and there is pressure at the rail, the oil pressure gauge is moving, and the RPM tach is jumping.

Now - I did drop the fuel tank about 3 weeks ago to fix my fuel gauge, the float was stuck. Put everything back up in and it was running fine for at least a few trips to work and back, no issues at all.

I am a bit lost here. Any help is appreciated. Thanks!
shemdogg SEP 15, 03:30 PM
Maybe the injectors arent firing? Try a squirt o starting fluid in the throttle body, if it fires right up, Id say injector issues. Tachs moving so you have spark. Post up the fix when you find it. Good luck!

shem
AsaBergman SEP 15, 05:11 PM
There's two things that can help here: spark tester and injector noid lights. Noid test lights you disconnect a wire to an injector and plug the wire into the test light. Determine if either the injectors or coils aren't firing.

I've never worked on a series 3 but the many 3800s I've handled you can have a tach reading but have no spark. I've upgraded the 3800s in my cars(Buick Reatta) to the later ignition module and coils your engine has. Tach reading comes from crank sensor and passes through the ignition module, it isn't dependent on the coils actually firing or even the ICM working properly. Another quirk is that the ECM can't detect a failing ignition control module directly. These modules are very prone to heat failure, this is even worse in the Fiero engine bay. When my ignition control module was failing it would only act up after I was driving and the heat built up in the engine bay. After that the car would have trouble starting resembling a failing fuel pump. A crankshaft position sensor can also be failing but only show symptoms part of the time. Sometimes the vanes on the harmonic balancer can become just slightly bent and lightly brush against the sensor slowly wearing the plastic cover off.

I'd say test your ignition control module and crankshaft position sensor. Crank sensor can be tested with a multimeter by reading one of the signal lines(there's two) and cranking the engine. Look up the pinouts and use wire probes(the kind you poke through the plastic insulation on the wires). Ignition module some parts stores like autozone can test. If you verify you have both pulse signals from the crank sensor but no spark then the module may be the culprit.
AndrewTHG SEP 15, 06:47 PM
Thanks for the help so far guys. I may try those injector noid lights. My other question is then, why the random starts? Just an intermittently working part that is starting to fail? And why did it seem like it would work until it idle down to ~1000RPM and then die each time? Is that a point at which it switches sensor or something to run, and may not be getting a signal? Again - thanks for all the help!
AsaBergman SEP 16, 08:54 AM

quote
Originally posted by AndrewTHG:

Thanks for the help so far guys. I may try those injector noid lights. My other question is then, why the random starts? Just an intermittently working part that is starting to fail? And why did it seem like it would work until it idle down to ~1000RPM and then die each time? Is that a point at which it switches sensor or something to run, and may not be getting a signal? Again - thanks for all the help!



Something to consider as well is failing ignition coils. I assume your series 3 is supercharged? You absolutely need healthy coils here. Luckily these engines use three separate coils so maybe try swapping a known good one in one at a time. You can measure resistance of the coils to determine if one is failing.

As for the random starts, the ignition module is VERY prone to heat damage. The variant of ICM your engine has helped mitigate this a lot but the issue is still there. It could run fine all day when it's 220 degrees but once it's 230 it'll decide to poop out until the temp drops. These things are such a pain I built my own tester for them.

One thing I can think of is the 3800 engines run in batch fire fuel injection mode until they reach closed loop. Batch fire does not require the camshaft position sensor. When the temperature reaches a set point the ECM switches to sequential fuel injection which uses the camshaft signal plus crank signal. On my 3800s closed loop(and thus sequential fire) is when it drops the rpm down from 1100-1200 to 750(proper idle). If you start the engine after it's been sitting overnight does it run fine until the temperature rises to around 160-170?

Have you checked the ECM for codes? Only part of the codes for these engines will actually trigger the check engine light.
Dennis LaGrua SEP 16, 02:40 PM
Easiest way is to connect at the OBDII port and scan for codes. Otherwise you are working in the blind.

------------------
" 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 "

AndrewTHG SEP 17, 06:52 AM
Bergman - yep, L32. I thought maybe coils but it's strange that I don't really get misfires so much as just nothing. With a coil going bad I would think the other two would work and fire.
Dennis - Sometimes it feels like I am always working in the blind

Honestly I've been doing a lot of brainstorming and researching but have only tinkered with the car a little bit to check fuel presure, plug wires, etc. It's one of those things where I just haven't had the motivation to tackle this problem just yet for two reasons: 1. I have tackled quite a few since it started running and it's gotten a bit frustrating and 2. I have been gone quite a lot and hate tearing into something just to come back and go "now where was I...?"

Anyway - first thing I'll do today when I get home is scan for codes and see what comes up. If nothing, I may undo the ICM and take it to Advance or somewhere to get it tested (having your own tester must be nice!).

I'm leaning toward something electrical having failed/failing...just not sure what that is. If it's the cam sensor or ICM, I won't be terribly upset except for the fact that ICM's seem to cost an arm and a leg for OEM. If it's a crank sensor I am going to be fairly upset, WHY DID THEY HAVE TO PUT IT BEHIND the crank?! There are plenty of crank sensors that can read from the side of the block or ANYWHERE else that wouldn't have been such a pain lol. I'll report back with what I find!
AndrewTHG SEP 17, 07:33 PM
Okay - update time.

I went out, try to start it, same thing as usual. Gave one breath of life but nothing after. Crank crank crank. Scanned the vehicle. No codes at all. Good news (I think?). So I jack it up in preparation of inspecting it tomorrow, thinking I will check wiring underneath, down the sides, sensors, grounds etc. I wiggle the connectors by the battery tray as well as at the ICM, and figure what the heck, I'll try to crank it over again. Crank crank crank boom. Starts up. Now...I have been leaning toward electrical and I don't want to rule that out just yet...but is it possible that my pump could have fallen out of the holder? I did drop the tank a couple weeks ago. But if so...woud it not pump correctly or maybe not be able to get fuel? I find that strange but at the same time, bad ICM doesn't seem to jive with jiggling wires or jacking it up. Maybe the pump fell to a point where now it is getting enough fuel to fire? To counter this point though...if there is fuel in the rail you would at least think during my many attempts at cranking it would have at least sputtered. Oh the joys! As always, I appreciate any input! Your guess is as good as....no wait...probably better than mine.
AsaBergman SEP 18, 10:00 AM

quote
Originally posted by AndrewTHG:

Okay - update time.

I went out, try to start it, same thing as usual. Gave one breath of life but nothing after. Crank crank crank. Scanned the vehicle. No codes at all. Good news (I think?). So I jack it up in preparation of inspecting it tomorrow, thinking I will check wiring underneath, down the sides, sensors, grounds etc. I wiggle the connectors by the battery tray as well as at the ICM, and figure what the heck, I'll try to crank it over again. Crank crank crank boom. Starts up. Now...I have been leaning toward electrical and I don't want to rule that out just yet...but is it possible that my pump could have fallen out of the holder? I did drop the tank a couple weeks ago. But if so...woud it not pump correctly or maybe not be able to get fuel? I find that strange but at the same time, bad ICM doesn't seem to jive with jiggling wires or jacking it up. Maybe the pump fell to a point where now it is getting enough fuel to fire? To counter this point though...if there is fuel in the rail you would at least think during my many attempts at cranking it would have at least sputtered. Oh the joys! As always, I appreciate any input! Your guess is as good as....no wait...probably better than mine.



There should be a ground cable mounted to the block below the bracket the ignition module bolts to, likely on one of the bolts holding this bracket to the engine. Ensure the ground cable and bolt here are clean and tight as the ignition module grounds through this bracket.

Pump: It's possible, not much holds these pumps in their bracket, but the hose that connects the pump to the fuel line wouldn't allow it much movement. A fuel pressure gauge would help. Just wondering, any idea how much gas is in the tank? I made the mistake of trusting the fuel gauge before.

Give it a bit then try starting the car without it jacked up and without fiddling with the wires.
AndrewTHG SEP 18, 10:29 AM
Yep, so that is one of the wires I wiggled, as I remembered putting that ground to that cast iron bracket, but it is so hard to see without removing the bracket to check it's condition. May pull the belt off and remove the bracket so I can give it a good look.

Good to know on the pump not being able to go far. I've been thinking about renting a FP tester too. I've probably got ~5 gallons or so in the tank. I had just filled it before this all started happening so I know there is some gas in there.

I'll see if I can recreate the problem again today. Lord knows I am going to try every possible wiring avenue before dropping that dang fuel tank again.