92 lumina euro 3.4 no start

[BumpRacerX.com]

Car ran like a beast yesterday. Fired it up tonight and it had a miss, found a kinked line, ran better but still had a miss. Died off and now it won't start.

Plenty of fuel at the valve. Unsure of spark or injector pulse. I know I have spark on the initial crank over as the car stumbles and fires and then dies. CPS is working because the tach moves when cranking the car over.

Pulled the plugs, they don't look great, but I've seen a lot worse.

Something to think about: Yesterday when I started the car I had to do a flood start routine (peddle to the floor, etc). No clue what would cause me to have to do this to get the car to start.

Background on the car: Bought it for $300 with the rear strut blown through the tower. The guy parked it at that point. Easy fix for me. The car ran great in the yard for me to this point.

[pocket-rocket]

Normally the only time you have to floor it is when it's flooded. When the ECM sees you floor it while cranking, it goes into clear flood mode, shutting off the injectors to avoid flooding it further. I wonder if you have some injectors that are stuck open. Were the plugs wet with fuel after cranking it?

[BumpRacerX.com]

Normally the only time you have to floor it is when it's flooded. When the ECM sees you floor it while cranking, it goes into clear flood mode, shutting off the injectors to avoid flooding it further. I wonder if you have some injectors that are stuck open. Were the plugs wet with fuel after cranking it?

See, that's why I decided to check the plugs first, but the plugs really don't look flooded. Old and covered with rust on top yes, wet no. I haven't checked the back side plugs yet maybe those back there are fouled bad. I'm gonna try to check tonight and see if there's spark or not. If there's spark then it's gotta be a fuel issue correct? What would cause the injectors not to pulse all the sudden?

[BumpRacerX.com]

Update: Put a new battery in it, even with one plug out (broke a wire checking things out) it fired right up. Appears to be heat sensitive condition. Next time it does it I'm going to video the tach so you guys can tell me if it's doing what it's supposed to do. Is it possible the crank sensor is still sending enough of a signal to read 800-1000 rpms (kinda bounces up and down when it was cranking but not firing) but not let the car start? Doesn't sound logical to me.

[BumpRacerX.com]

Update: Let the car run 10 minutes and warm up some. Shut it down. Now it won't start. The tach barely budges off bottom. How many RPM's will an engine turn over at using just the starter?

Also, I checked and have great spark at the plugs (or at least the one I pulled). So I'm guessing I have no fuel injectors.

[pocket-rocket]

I think mine turns at least 500 rpms when I crank. I know the tach does move (not just off the bottom) when cranking. I've never personally had a bad CPS, but I've been told when they are bad, they do usually stop working when hot (if they do work when bad), and I know for a fact when it stops working you won't have spark since the ICM get's its signal to command coils to fire from the CPS pulses.

[BumpRacerX.com]

I think mine turns at least 500 rpms when I crank. I know the tach does move (not just off the bottom) when cranking. I've never personally had a bad CPS, but I've been told when they are bad, they do usually stop working when hot (if they do work when bad), and I know for a fact when it stops working you won't have spark since the ICM get's its signal to command coils to fire from the CPS pulses.

So if I have spark it's not the CPS correct? What commands the fuel injectors to fire?

[pocket-rocket]

Correct.

When the crank trigger ring passes past the CPS, it sends a signal to the ICM. The ICM and the ECM have a two way connection. The ICM sends the ECM a signal telling the ECM what postion the crank is in so it knows when to fire injectors, and to figure spark advance. Then there is a signal sent to the ICM from the ECM for the spark advance event.

[BumpRacerX.com]

Correct.

When the crank trigger ring passes past the CPS, it sends a signal to the ICM. The ICM and the ECM have a two way connection. The ICM sends the ECM a signal telling the ECM what postion the crank is in so it knows when to fire injectors, and to figure spark advance. Then there is a signal sent to the ICM from the ECM for the spark advance event.

Could the CPS be sending a bad signal and causing the ICM to fire at the wrong time?

[pocket-rocket]

Well, if you know the engine is turning at the normal RPM with the starter, yet the tach is barely moving, it's very possible you have a bad CPS on your hands. Is everything stock as far as engine wiring harness goes? EI: no relocated coil packs?

[BumpRacerX.com]

Well, if you know the engine is turning at the normal RPM with the starter, yet the tach is barely moving, it's very possible you have a bad CPS on your hands. Is everything stock as far as engine wiring harness goes? EI: no relocated coil packs?

bone stock

Is there a way to check for injector operation without a noid light? Would a bad ICM create this situation? Run fine cold, shut down heat soak and fail but still put out a spark?

[pocket-rocket]

Usually when an ICM fails it won't fire coils at all. I believe parts store chains do have ICM testers, but the problem is getting it hot enough right there to simulate a previously run engine. The reason I asked about wiring is because some people have relocated their ICM/coil packs and didn't twis the new wire when they extended the CPS to ICM harness. The twists help reject noise, like networking cable. If you are electronically inclined, I my own noid light from a bridge rectifier, an LED and a couple resistors. The reason for the bridge rectifier was so I could be lazy and not have to worry about polarity for the LED, lol. I don't think a DMM would have fast enough of a sampling rate to pick up an injector pulse signal effectively, but you could try having someone else crank it while you pull the injector cover and put your hand on an injector to see if you can feel it cycling. I know the early DOHC ones are loud with that cover off, so I can't imagine you couldn't feel it while it's firing.

[BumpRacerX.com]

Usually when an ICM fails it won't fire coils at all. I believe parts store chains do have ICM testers, but the problem is getting it hot enough right there to simulate a previously run engine. The reason I asked about wiring is because some people have relocated their ICM/coil packs and didn't twis the new wire when they extended the CPS to ICM harness. The twists help reject noise, like networking cable. If you are electronically inclined, I my own noid light from a bridge rectifier, an LED and a couple resistors. The reason for the bridge rectifier was so I could be lazy and not have to worry about polarity for the LED, lol. I don't think a DMM would have fast enough of a sampling rate to pick up an injector pulse signal effectively, but you could try having someone else crank it while you pull the injector cover and put your hand on an injector to see if you can feel it cycling. I know the early DOHC ones are loud with that cover off, so I can't imagine you couldn't feel it while it's firing.

Any idea what kicks the injectors on? When you let it sit for a few minutes it fires for a couple cranks and then dies. I suspect that it's got leaky injectors and it's burning off the leaked fuel. Someone else suggested I check the TPS as it may be kicking the car into a flood start routine. If the TPS is bad though wouldn't it set a code when I initially get the car to run? How long would it take to set a code in the system?

[pocket-rocket]

The ECM triggers the injectors. I have no idea how long it would take for a bad TPS to trip a code. Do you have a means of scanning the computer while it's running. Not just the simple pulling codes scan, but I mean like a laptop that can datalog?

[BumpRacerX.com]

The ECM triggers the injectors. I have no idea how long it would take for a bad TPS to trip a code. Do you have a means of scanning the computer while it's running. Not just the simple pulling codes scan, but I mean like a laptop that can datalog?

I'm gonna have to buy a cable and some software I think.

Played with the car all day today. Crank and pop and crank and pop but no start. Spray a little starting fluid in the throttle body and it will take off and run and stay running. When it's running it's incredible. I've got an oil pressure gauge reading 40-80 psi for some reason, no clue what's going on there.

One guy that's good with 3.4's in the area listened to it run and said plugs and wires (no where to get the wires on a Sunday in BFE). He also said to check the firing order. My personal thought with the hard start is that the timing belt has jumped a tooth on one bank of cylinders, but why it would still start with ether is beyond me. I don't think the FPR is acting up because we accidentally pinched off a return line and ended up with a ton of pressure on the rail (hit the valve and it sprayed for a good 2-3 minutes like a geyser). If the FPR was bad that gas woulda ended up in the cylinders and in the oil.

The other thing is that when the car heats up it's about impossible to crank over. Even with an 1100 cca battery. We thought maybe there was a battery issue so we slapped the battery we thought was dead into a 3100 lumina and it cranked it over no sweat.