fuel injection problem. Need help?
 

I have been having this reoccuring problem with my 1988 5.0 LX Convertible. It is pretty much stock besides exhaust system and cold air intake. It is a Mass Air Flow car. The car is has no chech engine light on. It was orginally a AOD. New plugs, cap, eec IV and Map sensor. When driving the car in warm conditions for two hours. It has a loss of power and serges. I am only able to drive it by reving it up to 4 and a half grand untill it totally wouldn't work. It doesn't like high altitude driving. Does any one know what the heck is wrong.

I am having the same problem with my '89 bronco, and I think I got it down to one thing. The fuel pump relay. When my bronco did this, I took the relay off, and found that the conections were very much junked up. I cleaned them off, and haven't had the same thing since. Also u might need a new relay, if it does it when the motor gets warm, this would most likely be it.

Fuel Pump Relay
 

Relay ways all nasty, but it was replaced and and cleaned up and is still doing it. Any other ideas are much appreciated. Thanks

Are there any stored codes? Are you holding fuel pressure? Any vacuum leaks?

Help PKRWUD
 

I wondered if PKRWUD would help me. I have put some series money in to this car.

Exactly.

grant66-

I will try and help you, but you still need to answer those questions.

I don't see a vacuum leak being the problem, but I need to know what codes came up during KOEO, and if you have verified your fuel pressure, and whether or not it holds after the key is turned off.

Take care,
~Chris

Testing completed
 

So today I did the tests you asked me to. The Key On Engine Off stored codes were 29 and 66. Very weird because their wasn't a check engine light on. I tested the fuel pressure on the shreider valve and I came up around 220 KPA, which should be enough pressure.

Okay, you have a few things you need to do, and you need to do them EXACTLY like I tell you to, and in this exact order:

First, buy a can of electric contact cleaner, and unplug the MAF at the harness and thoroughly clean the contacts, then reconnect it.

Second, disconnect the negative battery cable, and then turn on your headlight switch. After ten minutes, turn the switch off, and reconnect the battery.

Third, Start the engine, and warm it up for 10 minutes. Drive the car to the end of your block, and turn so you're facing home. Put the tranny in low gear, and accelerate HARD to 25 mph, and then coast the rest of the way home. Shut off the engine, and run the KOEO codes again, and post your results.

Take care,
~Chris

Okay, after reading your PM, I still want you to follow my instructions in my last post, exept for #3, when you are at the end of your street facing home, shift to 2nd quickly, then drive it hard to 40 mph, and coast home. The rest is the same. If you can't hook up your speedo, estimate the speed.

Take care,
~Chris

Grant, sounds like a fuel pump or a weak coil. how many miles aree on your beast?

5.0 LX Vert
 

I have under 90,000 miles on the car. I hardly drive it. I lost the AOD in the car at 63,000 miles that was the second AOD in the car. So I put a t-5 in the car with a manual EEC IV. Can you believe it. I have under a hundred thousand miles on the car and three transmissions have gone into it. All my mods are a cold air intake and a header and x pipe. When I changed the car from a AOD to a t-5 I didn't hook up Clutch safety switch with to much power 12 volts instead of 5 volts. I smoked the brand new computer and a map sensor.

Any ways I have tested the fuel pressure it was 120 kpa. I believe the conversion is 40 psi. I would like to test the fuel presure when the car is acting like poo. That means hooking the fuel pressure into the car.

Followed your directions
 

So I did what you said to do PKRWUD and I came up with the code 29 (VSS). What do you think?

Unplug the VSS and test it's resistance with a DMM set to ohms on the 2k ohm scale. If the reading isbelow 190, or above 250, replace the VSS, reset the ECM again (disconnect neg bat cable & turn on light sw. again), and test drive it, then run KOEO again.

Post the results.

Take care,
~Chris

VSS
 

I don't know what the VSS is. May be I call it something else.

What year is your car, what year is the tranny, and what did your ECM come out of (year and model)

VSS=Vehicle Speed Sensor

Information about my car.
 

My ECM was just bought from Ford dealership it is an 5.0 1989 LX EEC IV. I have a t5 transmission I pulled it out of an 1985 GT. But the guy I bought it from said it probably was a later year t5. I don't know how to read the ID tag now that the transmission is in the vehicle. My car is an 1988 5.0 LX Convertable. It was made in September so it is a late model car. The car is a mass airflow car. Stock except for March cold air intake, Mac equal length headers and Mac off road X pipe.

Computer
 

My computer is also a convertable

Check and see if you have a VSS. It should be installed on the pass side of the tranny tail, and will have an electrical connector.

VSS probably was never installed.
 

My ECM was just bought from a Ford dealership it is an 1989 5.0 LX Convertable EEC IV. I have a 1985 t5 transmission I pulled from an 1985 GT. But the guy I bought the transmission from doesn't know what year car it came from. I don't know how to read the ID now that the transmission was installed into my vehicle. My car is a 1988 5.0 LX Convertable. It was made in September. So it is a late model year car. The car is mass airflow car. The car is stock for the most part except for the March Cold Air Intake, Mac equal length headers and a Mac Off road x-pipe. I would like how to buy and install an VSS. I thought manual transmission cars didn't have them on it. I know my AOD did.

I may have some bad news for you. If you installed a 5spd ECM into your car, and didn't disconnect the wire at pin 30 (in the 60 pin ECM connector), you are frying your ECM, and have possibly damaged it allready. You need to unplug the 60 pin connector from the ECM, turn the key on, and check for voltage at pin 30.

I will be around tomorrow to help you if you need it.

Take care,
~Chris

Can't find VSS
 

So I put my car on a lift last night and I could find the VSS. If I remember the AOD used the same hole as the gears for the speedometer. I believe PRKWUD said that the VSS was on the passenger side of the car. I did find a weird bolt that uses a male star bit. I did find the numbers on the transmission. Maybe we can start their. Borg Warner 13-52-066-919. Is this a t-5 transmission?

I sure hope I didn't fry my new computer. I will hopefully have that tested. I am going to be up set at these mechanics that have gone through three computers and two months of not having a car. They charge me $2,500. They did do some wiring work so hopefully it is good. I will test #30.

Pin 30 Test
 

65 DC Volts on pin 30 on the harness side of the engine. What do you think?

If your tranny doesn't have a VSS, then that's a problem. Your ECM needs the input from a VSS to help it make decisions. Look again, and write down the all of the electrical connections that your tranny has. Write down how many wires go to each, and what color they are.

Read the voltage at pin 30 again. There is no way you have 65 volts there. Make sure it's disconnected from the ECM when you test it.

Take care,
~Chris

Chris,
If you remember a while back I was having the problem with the 88GT only firing four cylinders. I also did the aod to t5 swap and am about to replace the computer on it since I never did it before, could this maybe be my problem, do I need to disconnect the #30 pin wire? I put a A9L in it out of my perfectly running 88 5speed coupe and now the coupe is running like crap with it back in there, I swapped them hoping it was the computer that was the problem on the GT. I think there is some wire somewhere shorting it out and frying the computer. Any input would be great, I have spent so much $ trying to fix this, I should have gave it to Ford for $70 an hour a long time ago

Yes, you will have a problem. Unplug the 60 pin connector, turn the key to ON, and check pin 30 for voltage. If you find none, have someone turn the key to START while you watch the DMM, and see if it has any voltage then. If not, you're good. If there is, let me know.

Take care,
~Chris

Did you get my last message?
 

I tested pin 30. Did you get my message? Is my transmission a t-5. How can I hook up a VSS?

Grant, scroll up and read my reply to you.

Chris,

Just to be clear which pin is #30, is there a specific color that it is on all of the mustangs, is the 60 pin connector numbered? I will be doing this on Sat, the car is in a garage in Tx right now. If you remember I was going to pull the motor, but decided to get it running first. I am going to try to double ground the injector wire also. I will perform the self code reader test Sat also and maybe that will get us somewhere, please don't forget about me and my problem I am about to push it off into a river. You are my last hope! I will let you know Sat, thanks Chris for everything so far.

LOL. No pressure.

Last I remember, I was waiting for you to test each injector with a noid light, when you decided to do something else.

Anyway, this should help:

I will do the noid light test Sat also. I hate to get my hopes up but i think we might get something this weekend. I will let you know Sat the codes I pull, the noid light test results, and if I have voltage on #30. Thanks again Chris.

Chris,

I tested the #30 pin and had 12.1 volts from it with the key in the on position. SHould I dosconnect it and leave it or what? Tha codes I pulled were as follows
#22
#14


Now the 12 and 14 were hard to tell , it was either a 12 and a 2 or a 14. There was a slight pause between 12 and 13, so we didn't know if we should keep counting or start over, if you keep going it is a 14, if you start over then we had a 14 only and a 22 only

Please let me know what is going on. Thanks

You have probably damaged your ECM. You need to cut and tape the wire going to pin 30, reset the ECM, and see what happens, but odds are you've already damaged it.

Take care,
~Chris

Chris,

Ok, I will run the tests again after taping off #30. You said before that I most likely damaged it if it was a 5 speed computer, but it is still the automatic computer, I was told in the swap from aod to T5, you didn't need to swap computers so I never did and really never had any problems. I am hesitant putting another computer in it because I am afraid I will just fry it again. I will let you know about the tests tonight or tomorrow. Thanks for all of your help so far. Oh yeah, we tried reseting the ECM and that didn't work either...

Then don't worry about the wire at pin 30. I thought I made it clear that this is only a problem if you have a 5 speed ECM in an AOD car (even if you now have a 5 speed). If the ECM is still an AOD ECM, it doesn't matter.

Go back to where we were before: get the noid light.

Take care,
~Chris

That explains why it fried the ECM I put in it, it was from a 5speed. Ok, I will test the harness with the noid light.

OK, as much as I wanted to find something wrong with the noid light test I didn't. All injector wires were pulsing..... Now what? Could it maybe be the pickup or the dist? Thanks for all of the help so far.

That surprises me. If it was the distributor, it wouldn't always be the same plugs that didn't fire, it would be a wandering miss. Have you tried changing plugs?

yes sir, twice.
:rolleyes:

My uncle just called and said that the spark from the dist would not jump out as far as the ones that were firing ok when he unpluged the non-firing cylinders. He said when grounded a screw driver out and then he held it over a terminal without the wire on it and it would spark up to it about an inch on the good ones, but on the bad ones, he said it would spark as far at all. Said it was an orange spark too.

Well, then it has to be the distributor, but I don't see how it is that the same 4 plugs are always affected.

Try this: move each wire on the cap one space over, then loosen the distributor and turn it back an 1/8th of a turn. This would be easiest if you make a reference point somewhere. Anyway, do that, and then see which plugs are bad. If it's the same 4, then it's not the distributor, but if the 4 bad ones have shifted over one spot in the firing order, then that clinches it.

Take care,
~Chris

OK, done, sorry it took so long, the same four cylinders aren't firing, it didn't follow the dist..........

Is there any way to test the TFI module? You don't think it could be that causing this pain do you?

You need a module tester, available at most auto parts stores for around $20.

I need to go through all of your info again, because quite frankly, I'm lost.

Take care,
~Chris

TFI module
 

I just took my module to Napa and they tested it. I burt up my ECM doing the same thing. I also hooked up my Neutral Saftey switch with too much power. I also fried my MAP sensor.

Yeah, I am sorry, see the car is in Texas and i am in Lousyana so it takes a while for me to test and post ya know... Anyway, I will get the mudule tested or just by a tester and post the results, I will go ahead and start a new thread too containing all we have went through, tested and done so everyone can be familiar where we are at with this. Thanks for all the help so far.