Well still having problems, Having intermittent problems The bronco ran perfect the other nite, ran smooth & idled perfectly. Then it started surging & missing, dying when you come to a stop. It did this before & after many new parts, including, computer, tps sensor, coolant temp. sensor, thermostat, distributor w/module, plugs, wires, cap, rotor, fuel filter, fuel pressure checks good. This thing will run perfect, then it will have a fit, then the next time you get in it, it may run fine. Have any ideas? Maybe injector problems? Any help is appreciated.

 

Year? I can assume a 1986-1988?

For the unsolvable problem, people have changed the valve assembly/filter cannister near the fuel tank.

BUT, I would look at the harness for the coil and the harness for the TFI module connector. Loose wires there are the most likely thing to cause random stalling without throwing codes.

Injector problems would be obvious by pulling a plug OR putting a timing light on each wire. A non-firing plug will be obvious.

I have a little spark indicator that lights up when pressed against a working wire, that has been pretty handy for figuring out boats, cars, mowers, chainsaws, etc. Not as reliable as a timing light, but, easier to use on a running vehicle.

 

Pull the vacuum line for the fuel pressure regulator. If it's 'wet' with fuel and you can smell fuel, time to replace the regulator. Another possibility is the O2 sensor or the MAP sensor, if so equipped. I'd also check to see if the throttle body and IAC valve are not dirty. May also want to do a wiggle test on the entire engine harness to see if there are loose connections, as well as check all your vacuum lines for leaks. There are two other things, one which rebo mentioned - the filter can near the tank (above it?) and the carbon canister. If yours has the two fuel pump/two fuel filter setup, you may want to check into that as well. If the low-pressure/return filter is gunked up, it will cause issues. Happy hunting!

 

Thanks for the replys I'll do some more testing, these intermittent problems are a pain.

 

Might want to also pull codes. If yours is an '86-'87 and there are issues with the EGR system at all, it will cause running problems, especially under load @ 18-2200 rpms.... I know this one first-hand

 

It's an 88 & it runs smooth w/ no load but under a load it surges & cuts out. I've spent way to much money on parts that weren't needed. The only code I've ever had was the coolant temp sensor which I replaced I haven't checked codes lately, this saga has been ongoing for 9 months. I have been thru the fuel system from the rear pump up to the manifold. We did have some gunk in the fuel lines, that got in there while it was setting w/ the fuel lines unhooked at the tank. (I had borrowed the tank and fuel pump for another bronco) but it's been all cleaned out. Exactly what problems w/ your egr system did you have kernel-panic?

 

I'd have to say if your problems are under load, to check the MAP, O2, and distributor pick-up, but FIRST do a wiggle test and pull codes to see if anything shows up to point you in the right direction. Another thing that comes to mind is if you have been keeping less than half a tank in your BII. Might have water build-up, might want to try some HEET.

The problem I have with my EGR developed after I did my cold air intake. I have a feeling that I either have a vacuum leak or somehow 'stopped up' the vacuum solenoid. I'll have to pull the lines and check the solenoid first, and if it's just that and not the EGR sensor, it'll be an 'easy, somewhat cheap fix'. If the EGR valve or sensor is bad (or both), it's not going to be cheap Can't complain, though... it's an '87 and has pretty much most all of the original sensors on it to the best of my knowledge Would not surprise me, though, if the EGR valve had been replaced at one time... the line from the exhaust manifold wasn't connected, or so I had noticed.... and between that and the cold air intake, things just started acting funny. It only 'stutters' on initial load and at the 18-2200 rpm range on the highway. Just got a few things to tinker with on it and I'll get it back to where it should be. Got a whole lot more involved with the '89 to do... got to figure out if it's a gasket or a cracked head that is causing coolant to ingest into #5 cylinder

 

Well I got codes 14 ignition profile pickup circuit failure & 18 loss of tachometer input/IDM circuit failure? spout circuit grounded. The entire distributor is brand new including the module on the back, wiggled wires no change, what do you think?

 

Differences in test mode noted as:
(O) = Key On Engine Off test
(R) = Key On Engine Running test
(M) = Memory code

14 Ignition pickup was erratic - Ignition Systems
18 (R) Check base timing & advance function - Timing Tests
(M) Ignition TACH signal erratic - Ignition Systems

You may want to very THOROUGLY check the connections for the ignition pickup inside the distributor as well as the TFI module and SPOUT, as well as the wiring harness inside the engine compartment. The only other possibility besides anything there is if your computer is starting to go south. There's info on checking the module and all that stuff in the Tech Info area as well as over on TRS in their tech library. You may also want to check the connector at the computer itself (it is located behind the passenger side kick panel under the dash, forward of the door). Another thing to look at is all of your ground points, ESPECIALLY for the engine management harness. These things are funny when it comes to having good, clean, tight ground connections.

Some interesting info on TFI troubleshooting here: http://www.therangerstation.com/tech...iagnostic.html

 

Well, checked wiring & connectors till I'm blue in the face. Took out the new distributor checked connectors and module, all good put it back together & was setting timing and the engine died like it does occasionally. This time though right after it died I could hear a sound coming from the injectors like a short circuit an arcing kind of sound for just a couple of seconds as the motor was shutting down. I repeated the process turning the idle down till it died and it made the arcing noise again but I could find no problem Can these injectors short out? I don't know.

 

Did it sound like a ticking sound sort of? I'd hate for you to spend $2-300 on all new injectors (I wouldn't replace just one or two, if it were me) only to find out that it wasn't the problem. Have you checked all the ground connections under the hood and on the engine, etc.? Could be that you have a loose connection somewhere. That can make an arcing sound. No signs of arcing or burning on any connector or in the wiring loom? Got to be something going on....

 

I've checked the grounds, the injectors normally make a ticking sound as they fire, don't they? This is more of an arcing sound. I was checking it in the dark because I couldn't find the source of the noise, It seems to be coming from one of the front two injectors. I tried wiggling their wires no change. I have an 86 parts vehicle I think I'll try some of it's injectors.