88 Bronco II dies when warm

[turmanator]

Hey, my 88 bronco II XLT just developed its latest problem. I replaced the tfi about 2 years ago (sat for a year) cap, wires, starter solenoid, fuel pressure regulator (within the past year and 1/2), pcv, ECT sensor, fuel pump relay, tps, cleaned the throttle body, new fuel filters, cleaned the injectors within the past month or so.

i pass on all codes KOEO but am getting a code 21 KOER but i just replaced the ECT, i am at a loss. I took a 450 mile trip with no problem until the last hill dropped me from 75 to 55 with the rpm going from 2200 to 1500 acting like it was starving for gas but it kept going, pulled over (had to piss) and it died on me than wouldn't start for another 15 minutes, would just turn over, and ever since everytime i drive 20 minutes it does the same thing, i can slowly put the pedal down but if i really try taking off it acts like it starves, only when its warm though. The HP fuel pump seems to be getting louder as well.

It idled fine for about an hour with no hesitation with the hood open, down it will die in about 15 min. my gas tank is rusty but the filter didn't seem to be clogged when i pulled it. Any thoughts would be appreciated. Also it has always ran rich and i do not blow black smoke. Pulled the MAP and it died so seems like its working, i checked the voltage of the TPS and it sat at 5v the whole time, idle and WOT which confused me. Thoughts?

 

[oksleeper]

Have you checked your ignition control module? Most autoparts stores can test it for free for you

 

[turmanator]

no, i didnt want to have to get back there and remove it if i didnt have to, put a new one one about a year or two ago and it has maybe 1300 miles on it? can they go out that quickly?

 

[bfiakas]

I had the same problems with my 88 and it was all a electrical.There's three electrical connectors under the master cylinder. With mine the connector where corroded and frayed due to over the years when the engine stalls and you try to turn the wheels and the power streering pump pukes fuild all over these connectors and eats them up.Check these and also the TFI to coil circuit ( dark green with yellow stripe wires),Ford zap welds their connections and overtime they get weak.Also rewire the ground at the computer direct to the battery.I also did a TFI remote to the inside of the cab which elliminated the heat issue.

 

[turmanator]

Alright ill check the connections and the circuit right now, ya i need to remote my TFI also

 

[turmanator]

checked one connection so far been cleaning it it was a little corroded. Should the fan turn on and stay on as soon i start the truck? will keep updating, i need this thing running longer than 20 min so i can get a job hah.

 

[bfiakas]

Use the electrical diagrams in the tech section to know what circuits you're chasing.If you have a rust problem,find all the grounds you can to repair if needed.I also ran a ground from the engine ground bolt to the frame. What fan, cooling or blower fan?

 

[turmanator]

Ok i cleaned all the connections on the driverside wheel well except for two that say PEP on it, it has 2 tabs ( one on each side) and i cant get it unplugged for the life of me but they seem pretty well sealed. Checked the TFI to coil circuit, got continuity and .4 resistance. warming it up to see if it dies on me with the hood closed than gona pull codes

The cooling fan for the radiator kicks on even on a cold start. my ground goin from the battery to the block is also routed to the frame as well.

 

[turmanator]

Also one of the plugs to 2 exposed wires at the back of the plug but werent burnt or corroded just covered in dirt/grime, cleaned those, the plugs didnt seem to have too much corrosion but i guess a little over a few places can cause a problem

 

[turmanator]

Yep just died on me while just idling with the hood closed. took probably almost 30 minutes, ran the codes KOEO 11, KOER 12,21 i think it did the 12 because i didnt WOT in time.

Since i already replaced my ECT i think i might just get a thermostat and a temp sender for the guage cause my temp guage barely moves when its warm, doesnt even get to the bracket and possibly another ECT, and probably flush my radiator while im at it.

Any more thoughts yall can conjure up ill definately look into, thanks yall.

 

[bfiakas]

Well code 21 is coolant temp. sensor out of range.Check the plug connection at the sensor or replace it with a new one.Does the fan clutch have resistance to it when you turn it by hand. If not replace it also.All unsulated wire will cause higher resistance in the electrical system and it will cause problems in the TFI circuit.

 

[turmanator]

when replacing the ECT i broke the tabs off the plug by accident, but seems to be seated well and stays in position, think it could be losing connection when it heats up and expands? Ill check out the fan clutch tomorrow, time to open a cold one now

 

[bfiakas]

It sounds like a TFI problem heating up and triping. I have come to find out the longest lasting TFi module I used and em using now are the Master Pro modules from O Reillys Auto parts.When you get to remoting the TFI.I just used aluminum foil for shelding with a bare ground wire and it work for me.

 

[turmanator]

When you remoted your tfi, what size guage wire did you use? Also, did you just snip the plug off with a few inches of wire, and just solder on the new wire to the existing and than soldered the plug back on? Thank you and sorry about the newb questions, i just dont want to mess this up, just broke my vaccum line to my FPR hah no biggy though, it was pretty brittle

 

[turmanator]

ok so my TFI tested good at Autozone, so i picked up another ECT and a thermostat and going to remote my TFI since i got it out now, the guy at O'reillys tried telling me remoting it is a bad idea because of vibration, but i've read plenty of stories of people remoting theirs with no problem, i think ill take it under the driver side dash.

 

[bfiakas]

Look for the section for remoting the TFI and follow the steps.I used 14 gauge wire on my remote.Make sure when doing the wiring at the distribitor that all three wires are cut even.I used a 1/8 piece of rubber cut to fit for a mounting platform where the TFI was and did the wire/spade work as per the remoting info. After I finished this part of the work I set the wiring to the rubber plate with RTV silicone so the male spades would'nt pull out when you reinstall the dist. I have A/C and I did'nt want to run the wiring harness from the dist. near the exhaust.So I went around the evap plenum and then down to the firewall below the heater plenum and made my hole there .Make a hole big enough to get both wiring harnesses through and then splice the six wire plug to the right wires.I mounted my heatsink to the bottom of the floor vent plenum were the vent blows on it.

 

[turmanator]

Alright nice thanks for the great info. Ya my cooling fan spins free and easy, ill be replacing the clutch tomorrow. Could i take the belt off for my a/c to free up some power? or will that put unwanted tension to the other belts? My a/c wont hold a charge so i dont use it right now thought i could free up some power.

 

[turmanator]

Also, when they do the module test, could it pass because the tfi is cold and not hot?

 

[turmanator]

ok replaced the ECT, thermostat, and temp sender, and kept the TFI in original spot, ill remote later, hopefully the ECT and or thermostat will fix my problem, i would check right now but have to go to rehearsal dinner, friend is getting married tomorrow, ill update tomorrow

 

[bfiakas]

Taking off the A/C belt may free up some power but it should'nt put extra load on the other belts.When they test the TFI module I have them run the test at lease 5 times.I, ve had them fail on the third test.