'90 beretta 3.1L no start

[zigroid]

Hello,

First, disregard my signature as this isn't the same car in it. It is a '90 beretta GT 3.1L w/ auto trans. body has 123k miles on it, engine was replaced by previous owner with unknown mileage. Tonight on way home from work the car lost power and I coasted to a stop, attempted to restart it but the engine would only turn over not fire. I could hear the fuel pump priming as I keyed off and back on so I figured I had a spark problem. After I got the car towed home I checked the schrader valve and it has fuel pressure so the pump is definitely working. I went to confirm the spark issue by having a friend shoot some starting fluid in to the throttle body as I held the throttle flat to the floor. The engine started to sputter as if it was trying to start so now I am pretty sure it is not a spark issue but is a problem with the fuel injectors not firing. After some searching I have found that if one injector goes bad on a bank the entire bank will go down I am not sure how true that is or is not but before I go ripping the manifold apart to get to the injectors is there any other way to test them? Are there any fuses I can check before doing this? Could a bad module cause an issue like this?

I have a chilton's manual from the previous owner but this thing is pretty useless at troubleshooting this sort of thing. perhaps I will have a reason to try out my new noid light on the injectors...

and assuming it is the injectors are there any relatively cheap places online to pick up a set or any other vehicles I could snag a set off of? I have a set of ford 19 lb/hr injectors laying around somewhere if they would work that would be great but all the info I have found points to the factory injectors being 15 lb/hr.

thanks for any help.

[Rettax3]

Hmm, okay... Check fuse #1 -that is for ECM and injectors. If you can hear the fuel pump running, then don't bother with the F/P fuse under the hood, otherwise, find the fuse mounted to the firewall right in front of the steering-wheel in the engine-bay.
Then...
1. Fuel spurting from the test port doesn't mean you have sufficient pressure to run the engine -get a test gauge and check it, and check it while the engine is running (or cranking, if the engine won't run) too. Look for ~47 PSI.
2. Buy an inline spark-tester. Harbor Freight Tools sells one for a few bucks, auto-parts stores should have them for a couple bucks more. Test all three front-bank plugs for spark, that way you have also tested the ICM and all three coils.
3. Now move on to the injectors. The only way a whole bank goes out from one injector dying is if it shorted out so bad that it fried the wiring, burned-out the ECM (unlikely, but theoretically possible) or burned the fuse (on your car that is fuse #1, and it would have taken out all six injectors in that case. F-body cars in that era use two different fuses for the two injector banks, not sure why L-bodies use only one ).
4. You can test the circuitry to the injectors with the noid lights, but the injectors themselves are typically checked with an Ohm-meter. I don't recall the correct resistance, I think Jon knows off the top of his head, and it has come up before pretty recently, so you might find it with 'search'... Chilton does not tell you. But, you can make sure they all read the same, +/- a few Ohms, and replace any that are open, shorted, or read completely different from the others.

Junk-yard injectors are usually fine. All GM 2.8 and 3.1 MPFI (NOT 3100 SFI engines) V-6s use the same injectors. I'm not sure what other engines do, but the 2.8s and 3.1s are still common enough, that should give you plenty to work with. Good luck.

[Money pit Beretta]

Check the crank sensor. It is about midway on the back of the block, inline with the crank. If that goes out then the injectors won't fire.

[3X00-Modified]

Check the crank sensor. It is about midway on the back of the block, inline with the crank. If that goes out then the injectors won't fire.

Spark plugs... the crank sensor is directly connected to the ICM.

[zigroid]

I went out yesterday morning and hit the key just to see if it started and sure enough it fired up so the problem seems like it will be an intermittent one. I haven't driven it yet as I don't trust it until I can properly diagnose the problem and I haven't had time to do so yet with work. I should have some time this afternoon or tomorrow. Thanks for the help so far guys.

[Hawk2010]

The map and coolant temp sensors handle the Timing of spark and when Injector spray fuel. Since it died at speed. I would start with making sure egr isn't stuck open. Since it started the next day I still would think egr. It could be closing slowly. Push diaphragm and see if it closes fast or slow. If slow pull it and clean it. I hope this helps . Good luck.

[3X00-Modified]

EGR would not cause it to die at speed it would cause more of a high idle due to a vacuum leak.... a bad crank sensor or ICM would cause this.. both will fail with excess heat and the ICM is under the exhaust manifold and the crank sensor is in the back of the block. Two items that will cause no start hot conditions as well as dying under speed.

Also to back up his theory, yes if an injector is bad it will take out the whole bank once again a heat sensitive failure. Best thing to do is look at the Chilton's manual and find the injector harness connector and ohm the pins for the banks... they should be at least 12-14 ohms each injector so add that up in parallel and that's the reading you should see, ~4.3ohms per bank... with them being at 13 each, remember resistance total is 1/Rt = 1/R1 + 1/R2 + 1/R3

[Rettax3]

I love Kirchov's Law...
My '89 GTU did a very similar thing... It started loosing power on the freeway, then a mile or so later just died and would not restart, no sputtering or anything else either, just a dry cranking... Later, it restarted and ran fine for a short time, then died again ~thirty miles later. It was a dying fuel-pump. So, although I am used to them just dying flat-out once they go, that could be your problem too... I say start with a proper fuel-pressure test.

[Money pit Beretta]

Check the crank sensor. It is about midway on the back of the block, inline with the crank. If that goes out then the injectors won't fire.

Spark plugs... the crank sensor is directly connected to the ICM.

Oops, too much on the brain and not enough brain.