Mass air conversion question

jdsmithinc · 09-24-2008

I have an 88 GT that I converted to mass air using a 90 model harness and computer. I also changed out the dash harness so that I would not have the fuel pump problem (wasnt really all that hard just time consuming) What I did not use was the harness that goes from the driver side kick panel to the transmission/fuel pump relay, and the back of the car. What I am having a problem with is the car will start up fine for about 5 seconds and immediately shut down. The fuel pump is priming, but I dont know about afterward. I also noticed that the backup lights come on when I turn the key on. Do I need to use the harness from the 90 model donor that goes from the driver side kick panel to the pump relay and such? Does my car need the air bag sensor harnesses to run? I am at a stand still at the moment. I still have the donor car, and will inevitably be changing those harnesses as well I am guessing. Also will it matter that the car this stuff is going into is a 5 speed car and the donor was an automatic?

kilog55 · 09-24-2008

did you disconnect the MAP vacuum line and plug the hose?

jdsmithinc · 09-26-2008

I did change the map sensor, and plugged the outlet for it. The car is starting up and idling real high (about 3200 rpm's) then shutting down. It takes a few times cranking it over to get it to fire, and it acts like it wants to fire, then she starts right up. I wonder if the 88 fuel pump is not pushing enough pressure for it to stay running? The injectors are from a 90 model also. There are no loose vacumme lines anywhere. There are 2 little electric things on the shock tower that are supposed to have vacumme lines going to them but they are not hooked up. Only the one for the egr valve above those 2 parts.

jdsmithinc · 09-26-2008

I have an 88 mustang that I did a mass air conversion on using the harness and computer, even the dash harness. I had a problem at first of the car firing up and running for about 2 seconds then shutting down. I finally got the car to start up and run just fine due to a little O-ring I did not put back in when I cleaned the IAC valve (DOH!!) Now that I got the car to run, and idle perfect it will not start back up when I cut it off. If I let it sit for a little while it will start right up after cranking it over a few times. When I try to start it after cutting it off it will spin over, I have spark, I have fuel, what the heck else is there? Could the engine be flooding out? There is no apparent smoke coming out from under it when it is running. Is the fuel pressure regulator going bad? Is the stock 88 fuel pump not working right, meaning should I use the 90 model fuel pump? I dont know what else to do.

Does anyone have a clue?

**EagleAutosports** · 09-26-2008

Is it a new kit? Is it a new mass air meter? Or is everything used?

jdsmithinc · 09-28-2008

The wiring all is used and came out of a 90 model car. As far as the mass air sensor, it is new. The computer is used. The car that all this was removed from was running before I tore it apart.

kilog55 · 09-28-2008

you plugged the line going to the intake and not the fitting on the MAP sensor correct? just for my own clarification. cause i forgot to plug the hose going into the intake and my 88 would do the same idle real high then die. then i remembered i forgot to plug the hose i removed.

chevyjdog · 07-07-2009

i got a a9l and wiring harnees that going on the firewall when i hooked up on my 88 the fuel pump dont work but if i run a jumper to my fuel pump relay under my drives seat it runs but all my stocl gagues acted funny and the oil presure gage dont work im i doing somethink wrong