Hello everyone! I originally posted in the electrical section, and have resolved the fp not working issue. My neighbor is 17 and bought this 85 V6 off his buddy for $300, not running. He thought it had a bad fp. I did some testing, replaced the fuel filter, and the fp relay. Now the car will fire right up and run! When you try to give it gas it bogs and dies. Sometimes it will even backfire throught the intake! I put my fp guage on the car and it idles at about 40psi. The idle is very high almost like a vacume leak. When you push the gas pedal the fp hits 45psi but the car bogs. I tried removing the MAF meter and it does the exact same thing. Open the throttle and it bogs, let it close and it runs great but with a high idle. The cel is on but lord knows what all codes this thing has! It's a real turd. It's like the injectors arent supplying fuel when the throttle is opened so it goes super lean and dies. Any ideas would be greatly appreciated. It's an 85 2.8/Auto.

 

Check codes first.... might want to clear them, start the car and run it to operating temp, and see what comes up. (leave the maf plugged in, as that is evidently not the problem)

Does sound like a vacuum leak though. Have you checked for those?

 

I've looked the car over pretty good. Nothing that could cause that bad of a vacume leak. The car was parked about a month ago when the car wouldn't start one morning. The guy thought it was the fp, but I later traced it to a relay. This car has so much electrical tape and shoddy splice jobs that it's a miracle it even runs. Yes, I think I can rule out the MAF meter as the problem. Super high idle and can't give it gas. Really sounds like a huge vacume leak to me but no luck finding it. Any way to check codes w/o a code scanner? Paperclip or something? The CEL has always been on, even a a month ago when the car was running great.

 

Take your paper clip, and jumper pins a and b. (should be the uppermost two pins on the top right side of the aldl.) Turn the ignition to "On", and then count the flashes, it will flash each code three times. Should get a 12 first (three times) and then whatever it thinks is REALLY wrong...... I think. Been a while since I have had to use that method...

Or, if the car is street legal, you could take it to autozone, or advanced auto, or probably any number of other parts stores, and they will read the codes for free.

 

I'll try that after work today. I cannot drive the car because it's idling at 2200 rpm and if I even look at the gas pedal it will bog and die. I'm going to look at the exhaust today. Maybe a clogged converter. My neighbor installed the fuel filter. What if it's installed backwards?

 

First thing I would check the codes then check the timing then for vac. leaks then the TPS voltage .

 

Ok guys, I pulled the codes. I got a 22 TPS voltage Low, and a 34 MAP sensor voltage low/vac high.

I cannot find a MAP sensor on the V6 to save my life. Anytone point me in the right direction? The TPS has 3 wires, blue, grey, and black. Which one do I pierce for a voltage reading? I'm a Ford guy so help me out here, .5-.99 at idle is ok, and then a smooth sweep to 5 volts should be correct right?

 

Little update here. I have fixed all of the dry rotted vacume lines. Starting the car takes several...... start, die, restart attempts. The idle really climbs at idle and any attempt to open the throttle results in stumbling and it will die if not released. I unplugged the IAC motor and the idle stayed high, and had no effect. I unplugged the MAF relay with zero effect. I backed off the tb adjustment screw all the wayto close the throttle blade. Idle still high with MAF unplugged, throttle blade completely closed, and I IAC unplugged. WTF! Ha ha ha! Checked the tps voltage and may have found a clue. I got a code 22 today so I searched how to test the tps on this car. Now when I probe the gray wire with my multimeter red wire and ground the black multimeter wire to the battery I was getting 4.6 volts. If I floored the throttle it only moved to 4.7. I removed the sensor and moved the spring loaded lever on the back up and down while the multimeter was hooked up. If I flick the lever quickly, the tps will drop to .5 volts then immediatly shoot back up to 4.6 volts. Sound like a bad tps sensor? I don't want to waste $50 of his money buying a new part if I don't have to.

 

Yes it is a bad TPS .

 

Ok, I installed the new tps sensor today and we got to take the car for a spin! There are still a couple issues to address so I will go ahead and ask. When the car is cold it will die 6-7 times after running for only 3-4 seconds. I don't know what would cause that???? Second, if I unplug the IAC motor it has absolutely zero effect on the idle. The car idled low at .56 volts on the tps, so I turned the throttle screw to get the idle to 650 rpm and the tps voltage is now .62. I still get a code 34 for the MAP sensor, but I cannot find the dang thing. Does this car even have one?

 

Code 34 on '89 and earlier MPFI V6 and TPI V8 is MAF sensor . Poor electrical connection , open or short in circuit ; defective MAFsensor ; defective ECM . Check the fuse for MAF and the MAF relay , and the MAF sensor . the brown wire to the relay has the fuse in it .

 

Perhaps the sensor is defective. It has 12 volts to the black wire in the middle , but no voltage to the large brown wire. Should it have 12V all the time?

 

You say you have 12v at the black wire an the sensor ? If so that is supposed to be ground and the orange wire with black stripe is positive from relay and the brown with white stripe is to the PCM .

 

It has 4 wires in this order. Large Orange, black, black with green stripe, large brown wire. I'm not sure which one of the two small black wires has 12V key on, but the other 3 have nothing.

 

It sounds like your talking about the relay . If so the brown wire will be hot at all times and the black and pink wire will be hot in start and the black and white wire will be ground and the orange and black wire goes to the MAF .

 

Yes, I'm talking about the relay. Two large wires on the outsides of the plug harness, orange and brown. I don't have a black and pink or black and white. I have a small solid black and a small black with a dark green stripe. Those are the center two wires. The last wire is copper or brown but has no stripe. I appears that all the wires except the brown wire run right up to the MAF meter.

 

I'm sorry, I was confused by the wire colors.

1st large orange wire----------------goes to MAF meter
2nd small black wire-----------------goes to MAF meter
3rd small brownish wire--------------goes to MAF meter
4th large brown wire----------------goes to a 20amp fuse on the fender. The fuse is not blown, but this wire has no voltage. Where does it go from the fuse holder? Looks like it goes under the car. To the fuel pump? I think it should be hot all the time. Sorry I'm so spuaddic(spelling?) I can only look at the car for about an hour a day.

 

1st is correct , 2nd ground ? , 3rd gauges fuse ? (hot in run or start) , and 4th is correct and should go to battery + . It probably connects at the starter or the distribution block . The distribution block should be on the frame near the battery . You can jump a wire from the battery to the brown wire and see if that helps . If so you are good to go but will have to trace the wire from the fuse to where it gets power from and see if it is hookedup or if it is broken somewhere .

 

Thanks for taking the time to help out this Newbie. My personal vehicle is a 1993 Lightning. I hope this final test getting 12V to the large brown wire turns off the CEL. I use to own an 89 Iroc. I really loved that car. I had removed the cat and run 3" exhaust from the stock cat location back to the rear of the car. If memory serves me correctly, it may have already had 3" exhaust. I added a single in/out flowmaster, 2 K&N filters, cut out the bottom of the airbox, and installed 3.73's with a shift kit. It's been 12 years but I seem to recall it running a slew of 13.9's on street tires. I think they were Michelin Pilots. They hooked great too! Anyway, thanks again and I'll post up the results.

 

Not a problem . I hope that cures the problem for you .