I recently Put a 305 With TPI into my 1988 GTA. it originally had this engine with TPI in it but the PO had blown it removed and let the car sit for 5 years.

The Engine came from a 1986 IROC. it cam complete with the full wiring harness attached and the computer.

Upon getting everything connected I attempted to start it. With starting fuild it would fire for a moment. Did some trouble shooting and determined that the fuel pump was dead. I've replaced the fuel pump but still having the same problem.

Right now to get the fuel pump to pump I had to run a jumper from b2 at the computer to the tan/white wire at the rear connector that leads to the fuel pump/sending unit.

by using my service manual and the tests provided it is telling me there is an open in the 120 curcuit. The 120 curcuit is the one that runs from the fuel pump relay back to the fuel pump.

The fuel pump relay is putting out voltage at the tan/white wire but does not get all the way back.

Also my fuel gauge registers way past full always.

Even though I've got power to the fuel pump now the car will start for around 1-2 seconds and then just dies.

Is this being caused because of the problem in curcuit 120?

Thanks in advance,

Robert

 

Here is a link for your application:

http://92b4crs.tripod.com/86wiring/dia-pics/22-2.jpg

B2 is connected to a common node that sends power to the fuel pump.

The way you have it wired, you can't be sure what is causing the problem. Try feeding a straight 12V from the battery, instead of off the ECM. If it still doesn't stay running, you have other problems.

 

Oh, and your fuel gauge problem could be because the car sat for so long. I had that problem with my GTA as well... I had to disassemble and clean the sending unit when I changed out the fuel pump.

 

By the book... my fuel pump switch is supposed to be by the distributor but in my wire tracing it appears to be above the oil filter which makes no sense... the oil pressure sending unit does appear to be by the distributor (unplugged it, no oil pressure). I have 12volts at the tan/white wire at the fuel pump switch.

Will try the direct to battery test.

 

By cleaning the sending unit... I did but to what extend did you clean it?

 

I took it apart. You have to be careful, because it is delicate.

The 'wiper' assembly that varies the resistance was covered in some kind of gunky deposit that shorted everything to ground, giving me a 'full tank' reading.

I soaked the pieces in carb cleaner overnight, and then carefully wiped it clean with a soft rag. Then I sprayed it with WD 40 a couple times to get rid of any little bits, and reassembled. My ohmmeter told me that I had taken care of the problem before reinstalling it.

My gauge works normally now.

 

My fuel pump switch is at the oil filter on my cars (I have three 3rd gens). It opens and closes with oil pressure. If your oil is full and pressure is good, it doesn't matter much where the sender and/or switch are... as long as they can read oil pressure. I'm thinking that having your sender up top near the distributor is a good thing, since a condition of low oil or oil pressure will affect your gauge reading earlier at that point than it will near the filter.

 

The fuel relay runs the pump for prime after car starts the fuel pump runs from oil pressure sending unit, if it will start but dies I would check oil sender. On your aldl conector you might be able to hot wire fuel pump to run continueous to test. look for a red wire put 12v to it it should run pump.

 

Okay... spent the day searching....

Found the c207 where the tan/white wire changes to brown... can't located the c313 that supposed to be in the front of the IP.

I ran a jumper wire from the brown wire at the c207 which now allows the fuel pump to run.

The engine will start for a brief moment. if I spray starter fluid in the throat it will run for about 3 seconds. If I don't it will run for about 1 1/2 seconds.

I set the timing at about 6 degrees ATDC by putting the mark there and turn the distributor by hand and watching my timing light flash. This is what allowed it stay running slightly longer.

Still have no fuel pump if I don't jumper a wire to the rear c313 connector.

What could be causing this (not running)? I'm told the engine ran prior to being pulled and shipped to me. The engine wiring harness was left intact all I did was plug it into my firewall connector and run the wires through the fender, and hook the computer up.

and help would be appriciated.

 

Could there be a problem with it even if it registers oil pressure? the brief amount of time it runs I do see oil pressure.

 

yes, if you have two senders at the back of the engine by dizzy one is for oil presure the other (two wires) is for fuel pump.

 

Is the single wire the one that you think might be my problem?

 

no , two wire should have 12v at org wire with key on tan wire gets power when presure is up and sends 12v to fuel pump

 

Hmm, seems I probed that connection and both had 12V at them with the key off... I'll check that again in the morning.... the one at the top... with one wire if I remove it it affects the oil pressure gauge... so that one is only for oil pressure...the two wire one is to drop the fuel pump if you loose oil pressure... correct?

 

OK... now it's time for some detective work. If you have 12V at the pump at all times, and the car does not stay running, that could mean that your injectors are not firing.

Since it is an 88 GTA, I'll assume it is at least similar to mine, which has a VATS system. Correct me if I am wrong here, but it sounds like you used the engine's harness in conjunction with your car's wiring.

If you plugged the engine's ECM into the same plugs that your old ECM was connected to, there's a chance that it's not a perfect match. You may need to re-pin the connector on the ECM... I'm not saying this is fact, just allowing for the possibility.

You need to get detailed schematics for both cars, and then compare them... check to see if the injector signal comes off the same pin as your old computer... and also compare the other connections inside the cab from one to the other.

 

org might be hot all the time , not sure but tan should only have power when presure is up, if oil presure drops it will kill the fuel pump.

 

that could have an effect on it.

 

that could have an effect on it.

 

thinking now that might have been when I had the curcuit jumpered, which would explain the 12v reading...

thanks guys... I've got some hope now...

 

Thinking about this in bed last night... I had an external battery running the fuel pump yesterday... even with that would a bad fuel pump switch on the engine kill the engine even though the pump is being powered from an totally different power source?

 

The Ecm and all the relays also came with the wiring harness.

the previous owner of my car stripped everything. I purchased the engine from http://camarofirebirdparts.com and he knew the problem I had so when he pulled the engine for me he inculded everything that was in the engine compartment and the computer all from the original engine.

the only thing I did was plug the large plug that is mounted on the firewall that shares the same plug and the engine compartment harness. the ecm came with the engine.

if the injectors weren't firing would it still actually run? it does run for a little tiny bit.

Robert

 

Do any of the auto parts stores have the ability of testing any of these components?

Where is the mass airflow relay located?

 

The fuel pump switch on the engine and the fuel pump relay provide power to the pump circuit. Powering the fuel pump from an external source bypasses any means of turning off the pump via those components.

 

I realize that the ECM came with the engine. But since it plugs into a harness under the dash (unless you have a different arrangement), is it not being plugged into the harness under the dash, which is on the other side of that firewall plug? Or did the guy provide you with all of that wiring as well?

If you are plugging the 'new' ECM in place of the old one under the dash, and the 88 pinouts don't exactly match the 86, that could be your problem. I suspect that the pinouts may be different because my 88 GTA has VATS, and the 86 did not. If your injectors are looking for a signal on the wrong pin, they will not open. In any case, I'd be troubleshooting the injector circuit if you are certain that the fuel pump is running.

And yes, even without that VATS signal, you could still get fuel during crank/start only... the following diagram shows that your engine has a 'cold start' injector, which will work during crank/start even without a valid injector signal.

http://92b4crs.tripod.com/86wiring/dia-pics/22-4.jpg

 

but will it actually run? this engine runs long enough to get me excited... but then stops.

 

I am starting to think you are correct.

the engine/computer/harness is out of a 1987 Iroc...
I'd be more than happy to trace out the pin out if I had the specs on both... I've got an 86 book... just swapped the computer with one from a 85 same condition... the fact that I'm not getting power to the fuel pump the normal way... and that the windshield wiper moter and pump have a different plug end on them tell me something changed from the 85/86/87 era to the 1988.

Do you have the pin out of the plug for the 1988? The plug I think we are both talking about is the larger half that plugs into C100

 

looking at my 86 manual, the only pin that has to do with fuel injectors is F4, so if it's not f4 on the 88 then that's the problem.

 

Unfortunately, I don't have that at my fingertips. The diagrams that I showed you were found from links on TGO, which only reference 85 and 86 models.

I'd like to get those diagrams myself, since I am still in the process of resurrecting my 88 GTA. All I have to work with is a Haynes manual, and the wiring diagrams are subpar and incomplete.

 

UPDATE

I found a site that has a lot of diagrams on it. Your injectors are signaled from D15 and D16 in an 88 5.0 TPI system.

Here is the diagram:

http://www.austinthirdgen.org/mkport...ine_wiring.gif

apparently, the pins are the same. I am studying them for differences... you might want to verify your ground connections for the injectors.

 

Okay... I called Hawks... they are only 20 miles from me and went over there and picked up a VATS Bypass. now I have no idea where the PCM is or what it is. Hawks says this is all I need.

 

Stupid question: Have you verified all fuses installed and good? There are 2 fuses labeled "INJ1" and "INJ2" that power the injectors. Before you go nuts, make sure that they are OK.

I don't think the VATS bypass will make a difference... unless the 1986 ECM is from a VATS-equipped car. You would need a VATS bypass if taking the ECM from a VATS equipped car to non-VATS, but not the other way around.

 

yes I think so... where is the ecm/PCM located?

 

It's the computer.

 

Oh...dah... thank you!!!!

I should have this going soon then!

 

any luck yet? Have you check for signal at injector plugs yet? you can test with a test light across the terminals when cranking.

 

no luck... the directions say... attach the blue wire to pin 25 on red connector or pin 55 on blue connector but I don't have either...

actually I don't think this is the right thing... it say it's for an engine from a vats system going into a car that doesn't have it.

and it talks about a PCM or a BCM

where would I check for the signal?

when I crank, it immediately starts, but then dies.

 

unplug one of the injectors use test light across the two terminals on conector have someone start it so you can watch test light it should flash when injectors are fired.

 

I'm all alone... do you know where the BCM is? I'd think it's near the steering column

 

what are you looking for the bcm for?

 

I have the option of connecting this thing I bought there also... but I just talked to the guy that made the key for me and he told me how to find it but it's back up behind the dash where you just can't get to.... I've lloked for a way to get behind the instrument cluster and I just can't see how you remove it.

 

can you check injector by your self, sit test light up where you can see it from in side

 

to be honest I don't know what an igniter looks like or where they are. I'm giving up for today... Sent an email to the vats bypass manufacturer and one to hawks... we'll see what they say in the morning...

thanks so much for hanging with me... dang sure would love to hear this thing run... been so close for 4 days now....

 

the injector is under the fuel rail ,goes into the lower intake, four on each side plus one for cold start, use any one except the cold start,(it is inthe center on drivers side) you pulled the new harness in to the body on passenger side and plugged ecm in to it from the 86 correct

 

yes except it's all from an 87.. I don't have a garage and the sun is setting here so I'll check those injectors tomorrow.

again thank you for your assistance...

 

87 should not have vats enabled on prom

 

I've got an 85 trans am too... I tried that computer and got the same result.

 

I've got this yellow plastic box (about2 1/2 X 3 inches) that is near the computer... not sure what the heck it is but I keep thinking it has something to do with it.

 

85 uses a different computer,
85= 870 ecm
86-89= 165 ecm
90-92= 730 ecm

 

if it's what I think it is it goes to speedo

 

yes that is it... no wonder there isn't any speedometer cable on the car... but now I need to find that thingy to go into the trans.

btw I took a flashlight out and looked at those computer... you've got those model numbers exact!