My '87 IROC (350TPI/TH350) began sputtering & missing like it was out of gas. A sort of howling noise was coming from the rear of the car. I thought the fuel pump had failed. Went thru the mightmare of installing a new one, plus the pulsator, filter, and relay. Engine turns over, but won't start. Was told coil was gone. Replaced coil...same problem. Engine turns over freely, but will NOT start! By the way, the "CHECK ENGINE" light DID NOT come on!! This is my first TPI car, and I'm groping around in the dark here. Can anyone help me out with a diagnosis?? I don't want to keep up this "piece-at-a-time" method. Thanks for ANY help. Quiet Bob

 

Hello Quiet Bob, any relation to Silent Bob ?

Okay, Back to Buisness.

Have you tested for Fuel pressure at the Fuel Rail? if not, Do so!

Next, Check To see if you are getting Spark. Pull off a plug wire, and stick something like a screwdriver in the end of it. Hold it close to a ground, while cranking the engine, if it arcs, then you Have spark. You may have to hold it pretty Close.


Remember, the Engine Only Wants fuel and Spark, with the appropriate Timing, to Run.


Once You have Checked these basics, get Back To us and we Can go from there.




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60 Ranchero - Project ( Money Hole )
85 Sport Coupe LG4 - Daily Driver

Just another Hot Rod kid, or thats what they all tell me.
Livin' the Stereotype

 

did you check all your fuses and fusable links?

 

Q-Bob,

Welcome aboard!

I see from the profile listed you are from Las Vegas. I know some habits are contagious, but stop gambling on part replacement and start diagnosing.

You need to determine if there is fuel pressure when the ignition is on. There is a Scrader valve (like a tire valve or air conditioning port valve) on the fuel rail on the right side of the engine. Remove the cap from this valve, then turn on the ignition. When the ignition is first turned on, you should be able to hear the fuel pump running for about two seconds. There should be pressure at the Schrader valve at this time. Wrap a paper towel around the valve area and lightly depress the center core stem on the valve. Fuel should spout from the valve if the pump is working. If there is pressure at the port, the pump is working.

If there is no fuel pressure, you need to make sure the pump is running. You can either get under the car and test the pump terminals with a meter or test light, of do it from inside the car. Find the ALDL (Assembly Line Diagnostic Link) connector under the dash on the driver's side. Somewhere in this area:



There is usually a rectangular trim cover over the connector. Using your meter or test light, check for voltage at terminal 'G' of the connector. This terminal should have 12V when teh pump is running.



If there is voltage at the terminal, the pump should be running. You'll need to get back under the car and check the connections to the pump, and ground wire.

If there is no voltage at the pump test terminal, you need to be aware that the pump will only run for two second when the ignition is first tuned ON, and the pump will not run again unless the engine is running or the ignition is turned off for at least twenty seconds, then turned on again.

If there is still no voltage, check the fuse for the pump. It is located near the battery on your IROC:



Since you indicated there is no SES light on the dash, the possibility is that the fuse failed when the pump failed. Since this fuse also supplies power to the ECM, the SES light would also not work, and the two second pump run would not occur.

If the fuse is O.K., you also need to check the fuel pump relay. This relay should click when the ECM tried to operate the pump on initial startup for two seconds. Locate the relay near the firewall and test or replace it with the MAF power relay to eliminate the possibility:



If the relay is O.K. but not operating, you're either going to have to diagnose the ECM, ECM wiring harness, or the wiring to the pump.

In the short term you can install a fused jumper from an ignition power source to the 'G' terminal on the ALDL connector to supply power to the pump directly. This should at least get you running while you diagnose the rest of the problem.

If you have fuel pressure, report back with your findings at the Schrader valve.

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Later,
Vader
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"I'm'a do Things My Way - It's My way or the Highway."
Adobe Acrobat Reader

 

 

Thanks, Vader. I've done all of the steps you sent to do. There is no fuel pressure at the Shrader valve, and there is no voltage at the "G" terminal of the ALDL. I ran a jumper from the "IGN" terminal of the fuse box to the "G" terminal, turned the key ON, and......nothing! The pump is not running. There is an odor of raw fuel coming from the engine compartment when I do this. I can hear the relay clicking on & off, but, that's all. The relaay is brand new, as is the pump. Now what???

 

haha vader, Quite the Comedian.


The pump is brand new, Did it ever work ?




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60 Ranchero - Project ( Money Hole )
85 Sport Coupe LG4 - Daily Driver

Just another Hot Rod kid, or thats what they all tell me.
Livin' the Stereotype

 

To Bort62: I am only assuming that the new pump works. It is a brand new AC Delco pump, as I shhied away from the option of a Taiwanese aftermarket type. I'm going to go back in and check all of the pump wiring, and see if I can find a clue there. Thanks for your help(I need all I can get!!).

 

To Vader & Bort62: Thanx so much for all of your help, guys! I finally traced the wiring from the fuel pump relay back to the plug at the tank. I found a broken wire at the plug itself, A little work with the soldering iron, and, I'm back on the road! Must have broken it when I pulled the tank out! Again, thanks for all of your responses to my problem. I wouldn't have found this without your help. Vader, you are one THOROUGH dude!! I learned a lot from ya'll! Hopefully, I'll learn more in the future.