88 Ford 4.9L TPS ?

[ADFD1]

Update, I used my buddies truck today, it has been driven about 30 minutes since we did set the idle strategy. This morning it started and stalled about 5 times, I drove it for about 20 minutes shut it off, about 8 hours later I started it, and it stalled about 3-4 times.

I took it home, and disconnected the battery in another attempt to reset the strategy. It started and stalled twice. I threw on the AC it stalled again, I stopped and started it a few times and left it. It is not good!

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[OVERKILL]

Almost sounds like the IAC sticking.

OR

It has a rich condition.

The first will cause stalling. The second will cause "hunting" which then leads to stalling.

 

[punisher]

Check upside down and backwards for any vac leaks, as well as any air leaks between MAF and throttebody. Warm it up, AC off, pull the IAC connector off and see what the base idle is.

Pull codes if you can (before disconnecting the IAC). If you have a scan tool with data link, pull up the fuel trims at idle to see what the heck is going on.

 

[ADFD1]

The IAC is new, as in a few months old, TPS new. No scan tool available, no vacuum leaks, EGR is working. I'm trying to help him, but might have to suggest he brings it to a mechanic.

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[OVERKILL]

For S&G's, make sure the TPS voltage is below 1V with the KOEO. Probe the middle wire and the black wire.

Otherwise, could be O2's.

 

[ADFD1]

I have this beast for one more day. Hopefully the first start tomorrow is better, I have my doubts. If I can I will fool around with it or talk him into a mechanic, since my tools, and right hand man (dad) are 3000 miles away.

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[OVERKILL]

EEC-IV is a very basic system. There are only a couple of things that can cause this condition.

 

[punisher]

EEC IV- you can pull codes with a jumper wire.

http://autorepair.about.com/library/ts/obd-i/bl-dtcs-60.htm

Ignore the DVOM hookup and look at the MIL flashes for codes.

I didn't initially pay close enough attention to the engine you are working on. It likely has a MAP instead of a MAF sensor. CK the vac line to it. Pull the hose off at the MAP, ck for any "jelly" in the line/sensor vac connector. ACTs act up on those as well and cause odd drivability symptoms.

 

[OVERKILL]

Its SD.

I used to own an '88 F-250 with the same engine.

 

[ADFD1]

Thanks for the replies. I had the truck today, start, stall 4 times. to get it going. Engaging the clutch while it was cold it felt like it had no power. The exhaust stunk. Turn on the AC it surges and searches until you put your foot on the gas to normalize it. 8 hours later cold start same problem, hot start no problem idles good has power, will stumble on occasion when engaging the clutch as idle drops.

Now I'm involved with this and will see if I can get the tools and pull a code. Keep the info coming and thanks!

AD

 

[OVERKILL]

Sounds like it is rich. As mentioned by punisher, make sure the MAP sensor is getting full vacuum.

This causes a loop with the ECM, that causes it to surge and die.

 

[ADFD1]

Guys thanks for taking the time to spoon feed this to me. Since it is not my truck and I'm helping a good friend. I'm not 100% sure of where things are located on this beast. I have some time over the weekend and will try and fool around with it.

Where is the MAP senor located on the Ford 4.9L engine? Once I find it I can follow the vacuum lines and see if something is out of order with it.

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[ADFD1]

Got it, its on the passenger side fender near the AC accumulator. I will have a look sometime over the weekend, and will probably have some more questions!

Will the MAP Sensor cause hard cold starting, then when the engine is warm it runs nice and restarts easily?

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[OVERKILL]

Originally Posted By: ADFD1
Got it, its on the passenger side fender near the AC accumulator. I will have a look sometime over the weekend, and will probably have some more questions!

Will the MAP Sensor cause hard cold starting, then when the engine is warm it runs nice and restarts easily?

AD


Not usually..........

 

[ADFD1]

Update:

When engine is cold, start stall usually around 3-4 times before it will run on its own. After the second of third start stall event the engine will run for about 45 seconds, race, surge, drop rpms and die. Usually after this it will start and not stall anymore. But it still lacks power until the engine gets warm.

When warmed up nice idle good power, however I noticed today when cruising in 5th gear around 50-55mph it feels like it is bogging down. Stepping on the gas resolves this. Bogging doesn't happen all the time, I noticed it in 4th gear as well usually around 1800-2000 or so RPMS, but it's hit or miss. No pun intended.

I am trying to locate one of those code readers that blinks out the codes. His check engine light hasn't worked for several years now so using jumpers and getting codes from there is not an option.

If I can't get a code reader my buddy is SOL and the truck will be off to the mechanic I guess. Or we could gamble and toss a part at it.

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[StevieC]

You need to find out the codes... Can you not replace the CEL bulb in the dash?

Also on those older Fords, there is a connector under the hood that is for a PRE-ODB-II scan tool. You could hook up to a multi-meter with and read the pulses in the forms of positive/negative voltages (codes).

What about that?

 

[ADFD1]

Hi Stevie,

I guess my friend Frank filled you in. My buddy and I are trying to get a scan tool. The way these Fords were set up was they had an amber check engine light that went on at a preset time to tell you to change the 02 sensor and check the emission system. I was told (so it could be wrong) that some of these lights you could reset, others had to be replaced. He said his had to be replaced and Ford wanted big $ for it, so he cut the wires to it. Pulling a bulb was not an option. Anyhow that is why we can't access codes from the check engine light, and why the scan tool is needed.

I'm to the point that if someone said sounds like part XWZ, I would have him buy it throw it in and reset the idle strategy and hope! LOL not a great way to do things, but something I've considered since I seem to have married this thing!

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[punisher]

I seem to remember there was an "emissions" light in addition to the MIL light on those. The MIL light doesn't come on at all with key on engine off?

 

[Jason2007]

Most parts stores will put a code reader on it for free.

 

[ADFD1]

Originally Posted By: punisher
I seem to remember there was an "emissions" light in addition to the MIL light on those. The MIL light doesn't come on at all with key on engine off?


No lights come on, and this is making this more of a project than I bargained for.

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