87 Celebrity Won't Start. Has Fuel and Spark, No Go.

[Brokecelebrity]

Okay, any ideas greatly appreciated. I have a 1987 Chevy Celebrity that I have used as my back up car for a rural mail route. A couple months back, in the middle of the route, it stalled on me twice. Like the fuel was cut off. I put the car in nuetral and turned the key and it started up and ran for another minute, then cut out for good. After playing around with it for a bit, I put some gas in throttle unit, and it ran until the gas burned off. As this was my back up car, I let it sit for a couple months, thinking it was the fuel pump and I'd replace it when I had time. I had another Celebrity a couple years back that had the fuel pump go out and it did the exact thing, once I replaced the pump, it ran great. So, last week I went and bought a new pump. Couple days ago, I decided I'd replace it and get the car going again. Once I had it jacked up and supported, I had the fuel line and the fuel filter exposed, figured, what the heck, might as well do an easy check. I took the fuel filter off, turned on the key, and viola, gas started pouring out. So, fuel pump is good, but, it still won't start. I have spark, and after disconecting the fuel line at both the firewall and the throttle body, I have determined that it has fuel pressure, but something isn't working right. I have narrowed it down to either the ECM, the fuel injector unit itself or the crank angle sensor. Anyone know the best way to check any of these possibilities to determine which it is? I can throw cash at a problem all day long, but I usually run out of cash before daylight, so I guess the first part of this sentance isn't true. Any help appreciated. Thanks.

[tomj76]

I take it that you have the 2.8L TBI engine. My '90 has the 3.1L MFI, so I'm not familiar with your engine, but I've read some about it in my service manual.

If you can start it by putting gas into the the air intake and you've verfied fuel pressure, then that suggests there's a problem with fuel getting from the fuel line to the TB. You might want to verify the correct fuel pressure, but your problem sounds more 'catastrophic' than low pressure.

You should be able to check the injector itself by manually connecting it across the battery (12 volts) using a couple of jumper wires. Also, I think the coil should have a resistance of ~10-15 ohms, which you can check with an ohm meter.

You might be able to check the spray on the injector by looking into the throttle body. If not, then you could remove the injector and check it by opening it with it on the fuel line, but spraying into a container while connecting it to a 12 volt battery. Make sure you're careful not to start a fire or explosion, since the gasoline spray is very volatile.

I don't think your car would run at all if the CPS were bad, if the spark is dependent on it for timing.

[jdl]

Originally Posted by Brokecelebrity

Okay, any ideas greatly appreciated. I have a 1987 Chevy Celebrity that I have used as my back up car for a rural mail route. A couple months back, in the middle of the route, it stalled on me twice. Like the fuel was cut off. I put the car in nuetral and turned the key and it started up and ran for another minute, then cut out for good. After playing around with it for a bit, I put some gas in throttle unit, and it ran until the gas burned off. As this was my back up car, I let it sit for a couple months, thinking it was the fuel pump and I'd replace it when I had time. I had another Celebrity a couple years back that had the fuel pump go out and it did the exact thing, once I replaced the pump, it ran great. So, last week I went and bought a new pump. Couple days ago, I decided I'd replace it and get the car going again. Once I had it jacked up and supported, I had the fuel line and the fuel filter exposed, figured, what the heck, might as well do an easy check. I took the fuel filter off, turned on the key, and viola, gas started pouring out. So, fuel pump is good, but, it still won't start. I have spark, and after disconecting the fuel line at both the firewall and the throttle body, I have determined that it has fuel pressure, but something isn't working right. I have narrowed it down to either the ECM, the fuel injector unit itself or the crank angle sensor. Anyone know the best way to check any of these possibilities to determine which it is? I can throw cash at a problem all day long, but I usually run out of cash before daylight, so I guess the first part of this sentance isn't true. Any help appreciated. Thanks.

I realize this is an old post, you probably have it fixed by now. You should have listed your engine size.

The way you tested the pump, is not a conclusive test. By the way, my info doesn't show a TBI 2.8L, it does for the 2.5. I've seen TBI injector spray patterns that looked ok, but when I checked the fuel pressure, it was half of what it should have been. On some models, I have removed the fuel pump, layed it on the ground, hooked up battery voltage to the pump, it took off like a bat, throwed gas everywhere, you'd be surprised how much gas that little pumpbody would hold. I guess I'm lucky, I didn't start a fire. That little test didn't make any difference, I knew the pump was faulty. Did you ever check fuel pressure?

[16th hippy]

could it be just a restricted filter?

[Brokecelebrity]

Thanks for all the info. I did replace the crank position sensor and that was the problem. After I installed a new one, I was able to get fuel into the throttle body, but, as I had the fuel injector "straight wired", ie, the old fuel injector connection was trashed, so I had the injector wired to the battery, for initial test, I got a continuous flow. I have a new connector on order, think that should do it. Thanks.

Edited to ad, it is a 2.5.

[tomj76]

I'm sorry about the 2.8l/2.5l confusion. I didn't remember the size of your engine and took a guess assuming that close was good enough on that point.

I have to admit that I was surprised the CPS replacement fixed the problem. I thought the CPS could not cause this because I didn't believe you'd have spark without it. I believe the 3.1l electronic ignition requires CPS input to generate spark at the proper time. I'm going to check my service manual just to understand this a little better, for my own information.

When I jumpered my injectors, I used a couple of small allegator clips to connect them to the battery.

Thanks for posting the update.

[tomj76]

I don't want to seem argumentative here, and since replacing the CPS solved the problems then that's what really counts, but I reviewed my manual and the only symptom listed in the troubleshooting charts for a bad CPS is no spark.

However, since the CPS signal is also used to control the fuel injector, the connection for that signal is from the DIS module to the ECM, the car ran with gas added to the throttle body, and your work to replace the CPS fixed the problem, then I wonder the actual cause was a loose connection between the DIS and the ECM, or another electrical connection that was fixed in the process.

Either way, it's a moot point now, since everything is working.

[16th hippy]

hey tom, you have an interesting point there. I've seen it where the sensor was melted a bit inside, and was reading the reluctor on the crankshaft wrong. car ran like dogshit. replaced sensor and all was well. seen another one where sensor was caked up with a bit of oil sludge and did same thing, cleaned sensor and away it went. there are times when it will send the signal, but signal at wrong time could cause a no start even though it gives a spark, but maybe not right signal getting to pcm to fire injectors. is kinda weird, but could happen. moot point or not, it jarred my memory, just wish it would have sooner to help brokecelebrity...lol.

[Brokecelebrity]

Tom, you could be right about the possible elctrical connection. The car ran great 7 years ago when I got it, it had about 150k on it then, and it now has close to 250K, it's had small problems now and then, but when it went out, I was pretty sure it was the fuel pump as the signs were the same as my other one that had a bad fuel pump about 8 years back. The old CPS that I took out "looked" good, ie, no dirt or crud fouling it, but with the instal of the new one, car starts everytime, hot or cold. All the attachments and connections to the DIS were tight when I took it off, and on the 2.5 engine, I doubt it could have been in a more inconvenient place, halfway down on the backside next to the firewall. Thank goodness for angle head socket wrenches. Anyways, it would be good to know if it was the CPS or a loose electrical connection somewhere else, but, it runs now. Thanks.