I have a '85 TA with a 305 TPI. I have just put in new plugs, wires, cap and rotor. I was also trying to fix my cold start problem when the problems began. The engine is a '89 and the ECM is a '85 so no cold start. I got '86 runner, plenum, fuel rail, injector and switch and swapped them in. I also replaced the egr valve.

The car will start but dies right away. I swapped the original parts back in when the problem started. I don't have a vaccum leak, the fuel pressure is at 35-40 PSI. The car will run as long as I give it gas. I pulled a code 34, too. I can't hear the fuel pump prime when I turn the key to on but I haven't heard it in a long time. The car still ran though. Also, when the engine cuts off, the fuel pressure falls to 0 PSI(not at once, but fast enough to notice it on the guage). Isn't the system supposed to remain pressurized? I don't know what else to do. I thought, egr first, then vaccum, then ignition, now I think fuel problems, but I want some other opinions.

Any help will be appriciated.

Matt

 

You need to check if the fuel pump power is being turned off after the engine starts. Use a volt meter at the connectors near the tank and see what happens.

If it is being turned off, that could be a number of things, ranging from the computer not getting the message from the distributer that the engine is turnng over, to a faulty relay. You would have to use the voltmeter with the wiring diagram to chase that down. My book of codes says 34 is MAF sensor out of range, have you checked the MAF.

Don't just go changing parts, because you could get through the whole car before finding the right fault.

If the power stays on to the pump, then a few major things can cause the presure to fall off, a bad pump, or a bad back pressure control valve, blocked filter, not enough gas in the tank etc. You can check if it is the back pressure valve by squeezing off the return line rubber hose and seeing if that brings the pressure back up.

What was the cold start problem? Are you sure the different control systems you have are compatable?

Maybe try the question on the TPI board

 

The wires for the MAF were bad so I spliced new ones in, I also swapped MAF's with a '86. I don't have a MAF that I know is good.I also don't have a voltmeter. I put in a fuel filter today. All the parts I bought and put in are maintaince parts. I didn't know the last time they were replaced. I can feel the fuel pump relay by the firewall click, but I can't hear the pump turn on. It's been doin this for a while though. Isn't there another relay for the pump?

Cold start problem: My car is a '85 with stock '85 ECM and harness. The engine is a '89. I lack the cold start injector, switch and any means of putting them on the engine( except the necessary wiring, as its a '85 harness). I have all the parts(driver side runner, driver side fuel rail, injector, switch, and plenum off a '86. I was told however the parts aren't compatible with my '89 intake manifold.)

Also, there is a burning smell of some sort, not oil or coolant I don't think, maybe its running rich or the new gaskets are seating? It hasn't been running so it hasn't reached normal temps in a couple weeks. I checked the exhaust color but it is very cold(low 30's, high 20's) so the exhaust is white.

Any other ideas? Maybe bad or leaking fuel injectors?

Thanks

Matt

 

Hi Matt
If you don't have a voltmeter, just get a 12 volt bulb with a couple of wires and use that to check if the fuel pump is getting power. I don't think there are two relays, only the one yo know about.

You can make a choke by putting some sort of flap in the air inlet, maybe over the airfilter to restrict the flow of air when starting and warming up. It wont suck in more gas like a carb would, but it will increase the fuel air ratio a bit, maybe enough to get the engine running. let it warm up a bit before touching the throttle.

Are you sure you need a cold start injector. The earlier one don't have them, they just inject more gas until the engine is warm.

Burning smell could be anything, but check it isn't the wires that supply the fuel pump. Check nothing is touching the exhaust anywhere.

Good luck.

By the way, you can't assume that a new part is in good working order. I check everything and work on the basis the new part could be faulty, because so many are.

 

I got friend coming over this weekend to help out.

I'm positive I need the cold start injector. The '85-'88 TPI's used it. In '89, cold start was achieved by a program in the ECM that made the injectors inject more fuel into the engine when cold. The cold start injector accomplishes this in the '85-'88's by injecting fuel for up to 8 seconds duration(I heard), until the engine starts. My only option is to put the injector and other parts in or update my harness and ECM to a '89.

Also, my fuel pump continues to run for a sec or two when the car dies.

Thanks for the help.

Matt

 

I am having the exact same problem as you. For me I think I narrowed it down to a bad MAF sensor. I will let you know on Mon or Tues when my new sensor comes in if that fixes it. I know my problem isn't the pump because it is brand new and the relays checked out ok.

 

You should realize that the 1985 MAF is different than the 1986-89 MAF sensors, with a different signalling protocol. The 1985 system used a frequency modulated signal at a fixed amplitude. The 1986-89 system used a variable amplitude signal, so you cannot simply plug one into the other and expect it to work correctly.

 

vader- I just realized the that this weekend, but I wasn't completely sure.

I called a couple mechanics, they said it sounds like the fuel injectors aren't working right. I'm gonna send it in tomarrow or Wed for a diagnostic check. I'll post what they find.

The fuel injectors make more sense now. Prior to these problems I noticed when the engine is cold and I hit the throttle it jumps, hesitates, jumps, then hesitates like the trans is slipping. Also, on hard deceleration, the engine would stall, like its flooding, so the injectors might be leaking or something. The car usually wouldn't start right back up. It would take 5 min or so. When I cranked it it seemed like the battery was low, then it would crank fine, then the battery seemed low. It would do that for 5 min then it would get better and turn over(after pumping the pedal while cranking). So, I'll get the injectors and car checked and I'll post what happens. Hopefully this resolves the problem.

Thanks to everyone who helped.

Matt

 

I took it over to Auto Lab today for a diagnostic check. When the guy popped the hood and saw all the loose and cut wires he said I had a real mess. He didn't realize the they were for the AC and cooling fans. They told me they weren't sure they'ed find anything since the wiring was bad(didn't use those exact words but it sure sounded like thats what they meant).
With a diagnostic check, they test the sensors, wiring, and computer, right? Can they tell if an injector is not firing or if they are clogged or broken/not working?

I just realized I'm not sure what exactly they do when doing the check.

Matt

 

The car is finally running again. Autolab found a bad Idle Air Control motor(they called it Idle Speed motor). It looks way different than the old IAC though. Also, They have the stop screw on the throttle body out so far I can see the threads. Is this right? They wouldn't guarantee anything. The car does not idle well when the engine is cold. It sits right at about 700rpm. If it sits to long it drops and drops then dies. After being warmed up the idle is fine, it drives fine but after driving when I put it in park it idles constantly at 1100rpm. Whats goin on here?

Matt

 

I had the same exact problem with my 87 2.8. It drove me nuts.... I though EGR..nope.. o2....nope.... plugs etc.... nope... then i unplugged my MASS air sensor... and there it was full power no hesitation. good idle. It seems that it was bad and it was leaning out my fuel too much.. I hope this is your problem also.

good luck

 

You should take it back and ask the mechanic to adjust the idle.

 

Sorry it took me so long to reply, my computer is stupid.

I was thinking MAF too. But in closed loop the car runs well. Except on a sudden deceleration it will stall on me. It sometimes takes a while to start again. Sounds like flooding when cranking. Cranks fine, noe start, then cranks slow, no start, then cranks fine and starts(sometimes, will repeat patterns other times.)
I also suspect the oil pump or switch is bad. I pulled a code 54. Also, after oil changes there will be no pressure for a few seconds and the SES light comes up. Also, when trying to start when cold, the pressure takes a while to build, 5-10 sec. When the pressure is there then it will try to want to start. (be aware I don't have a cold start injector and my car is a '85) Could the pump cause the stall problem too? When it stalls sometimes there is very little or no oil pressure. Also, when braking maybe my oil pressure suddenly drops and that knocks it out?

What do you all think?

Thanks

Matt