Savage_One

Vehicle stopped running while driving, mechanic at tow shop said injectors were out of spec but said something about the ECU or "Brain" being possibly responsible, so after towing it back home I removed a spark plug and got spark while friend was cranking it over but didn't even smell fuel coming out of the plug hole. I'm working on getting the diagnostic tester to see the engine code because it is showing the engine light but I didn't ask if they checked it because i didn't get a trusting vibe from them. (Rechecked the dash and its a "Service Engine Soon" light, and the car has 199k on it so is that mileage based service light?)

Is there something I can check and see, I'm planning on replacing fuel filter as well, in case it is clogged but I haven't gotten that far yet.

I have a multi-meter if needed to check out any electrical. I'm trying to get a free service manual online but I registered here to get some other input.

Thanks for your time

Savage_One

Okay so I looked online for the OBD diagnostic wiring diagram, read that I could ground the connection for the diagnostic and count the blinking Engine Light for a code. Well I jumped the two connections, turned the ignition on, and the electric fan kicked on.

I then noticed that when trying to start the car, the Temp light came on, with it jumped or not.

If Temp sensor isn't working, thus incorrect fuel delivery? Any input would be appreciated, thanks.

ShadeTreeJack

Did the light blink? what codes were read?
I think the fan coming on is normal when you jumper the A and B terminals to get the code. I had a '91 Camaro with a 3.1L that quit more than once when the fuel injectors were out of spec. It would start when primed, that is, use starting fluid into the intake or pour gas ( not recommended, but I do it in a pinch) If it runs real good for a few seconds, spark is clearly OK - fuel delivery isn't. do you have an Ohm meter? my solenoids dropped low on impedance to around 4 or 5. the good ones were higher, I think the spec is 10-13 ohms, ( or 8 - 15 can't remember exactly) I also had problems with just about every sensor under the hood. $$$

Savage_One

Okay so when the "A" & "B" diagnostic connecters are "jumped" to get the code, I get a repeating 1-2 signal, which is "diagnostic mode" from what I understand so far. I've "Ohm-ed" the two injectors that are reachable without removing the Intake plenum, which fell way beyond spec at like 2.something to 3 ohms each. I've read that spec is 12 ohms.

Spark is fine as far as I can tell, I don't have starting fluid or anything I would trust spraying into the intake, at least not at the moment. I could eventually try a spray bottle of gasoline to see if it sparks good....

So, I know at least 2 injectors are out of spec, which probably caused the ECM ground fault I've read is common. So if all im looking at is 6 new injectors (or pick'n'pull) and a $85 computer, I'm happy

I got the car for $100 to the owner plus $75 towed to my house, a friends mom didn't want to spend the money on getting it fixed, and decided to help me out as well. It has about $2100 invested just last year in struts, alternator, battery, power steering pump, water pump, serpentine belt, etc. so whatever I have to spend on it to get it running for myself or re-sale is worth the time and $

Thanks much for the reply and input!

ShadeTreeJack

I would try just the injectors first. Autozone might be able to test the ECU - I've read that here, but I don't think they do that around where I live. Also - the library might have a book like Haynes or Chiltons. you can usually check their inventory on line

mediaman67

do you have fuel? - did you check for pressure at the rail valve? KOEO you should have at least 30-40 PSI...

I'd check that, before replacing the injectors - also, if the car has 200K on it, and it's the original sending unit/fuel pump/filter, those would be the first place I'd look...

Also, I'd check your ign coil packs - I assume that the 91's still didn't use a Dist? we have a 93 with the 3.1, and have seen it all.... (just about)

coil packs can flake out, and be ok the next second... GM put them in a really dumb place in the 93 (not sure about the 91) - but right next to the header on the right side of the engine... surprised they don't melt to be honest.... oh well - all in all, it's a better car than anything they make now for under $20K

Savage_One

I have fuel, half of the tank. Fuel pressure is good at 35.

I got it to start a few days ago after I had disconnected the ECM, then disconnected the battery (it had died) and found the engine ground wires, cleaned those off then decided that I would try to start it, so I put in my Optima battery from another vehicle, and it fires right up, idled rough and would die when given gas, unless the pedal was stomped and then brought back.

I'm really leaning towards the injectors as the culprit, and I've just boughten a refurbished set from PrecisionAutoInjectors on eBay for $84.99 + $7.99 shipping.

I already know that 2 injectors are completely out of spec. When the injectors come I'm also getting a new fuel filter just to eliminate that possibility and since it is the stock filter it's due for replacement anyway.

I'll keep this updated, I owe this site a lot for guiding me in the right directions.

Savage_One

Put in new injectors, it fired up and has been driven a few hundred miles since with no problems.

grand am gt 1998

I have a 91 chevy lumina 3.1 liter replaced the crank senor had coils and ignition control module checked all good checked all the grounds they r good replaced timing chain getting fuel to motor but I cant get spark I will get a tiny spark every once in awhile but then nothing I was told the ecm could be the blame but not sure does anybody have ideas