'88 'Burban Update...

Look at the EGR valve:

Sounds a bit like tip in hesitation. Can you tell the difference from a stumble to a hesitation?

A stumble the engine almost dies, then jumps like a bat out of hell, a hesitation slows, then gradually picks up.

If it's injector related. You'd have more of a stumble condition from the rich mixture.

The injectors are best checked with a residual pressure test, after the key is off, there should be a negligible pressure drop, and it shouldn't drop for days.

I hope this helps?

Refinish King

FPR...Previous replacement of the base

over all power, and starting! I still

have a stumble about 1300RPM that

together. I think it might be the

disassembled, would it help if I monkeyed

If I keep the throttle at that RPM she will die!

| >

| > I replaced the IAC valve and the oxygen sensor and rebuilt the | FPR...Previous replacement of the base | > gasket and cleaning of the TBI | >

| >

| > EVERYTHING is better(not perfect), Idle quality, throttle crispness, | over all power, and starting! I still | > have a slightly higher idle(1100RPM) unless I crack the throttle. I still | have a stumble about 1300RPM that | > clears up with slightly more throttle or with getting off the throttle all | together. I think it might be the | > pintle adjustment on the IAC valve... | >

| > How do I get the proper setting on the IAC valve pintle? | >

| > I noticed that spring tension can be adjusted on the FPR with it | disassembled, would it help if I monkeyed | > with it a little? | >

| > Could I have warn or faulty injectors? | >

| > Any other ideas anyone wants to throw into the mix??? | >

| >

| | |

Either fuel pressure:

Fuel on the rich side, or maybe a long shot. But, a distributor pick up coil.

The best I can do with a seat of the pants diagnosis, without more symptoms. When it dies, does it stumble on, or just die flat?

Refinish King

The TBI systems have an "autobleed" feature where they bleed off pressure when the pump ain't running. Takes anywhere from 1-3 hours for the pressure to completely bleed off. This is why it isn't necessary to relieve system pressure on the TBI trucks before cracking a line if they've been sitting a few hours. CPI and MPFI systems on the other hand should hold the pressure indefinitely.

Doc

She will stumble down until she dies if I hold the throttle in the stumbling RPM range. She will fire right back up though with no problems.

| >

| >

| > | >

| > | > I replaced the IAC valve and the oxygen sensor and rebuilt the | > | FPR...Previous replacement of the base | > | > gasket and cleaning of the TBI | > | >

| > | >

| > | > EVERYTHING is better(not perfect), Idle quality, throttle | crispness, | > | over all power, and starting! I still | > | > have a slightly higher idle(1100RPM) unless I crack the throttle. I | still | > | have a stumble about 1300RPM that | > | > clears up with slightly more throttle or with getting off the throttle | all | > | together. I think it might be the | > | > pintle adjustment on the IAC valve... | > | >

| > | > How do I get the proper setting on the IAC valve pintle? | > | >

| > | > I noticed that spring tension can be adjusted on the FPR with it | > | disassembled, would it help if I monkeyed | > | > with it a little? | > | >

| > | > Could I have warn or faulty injectors? | > | >

| > | > Any other ideas anyone wants to throw into the mix??? | > | >

| > | >

| > | | > | | > | | >

| >

| | |

Thanks for that note Doc!

I haven't done a long term pressure test on a TBI, remember the fixture I told you I made. Just done some quick checks and got the hell out of there!

LOL

Refinish King

Take a look at your TPS voltage at idle position:

Then do a TPS sweep with an analog meter, to see if there any missing spots on the carbon rheostat, best checked with a square wave meter. Like a lab scope or a cheap square wave counter for a VOM.

Also, have you ever checked the plugs, wires, cap and rotor?

Refinish King

stumbling RPM range. She will fire right

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TPS sounds like a REALLY good guess based on what he's describing. The VOM will tell all.

Doc

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I'm gunna make me one of them when I get a free minute. Might make it exciting and use a USED fuel filter, he he he he.

Doc

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That's what I did!

That's why I use it and get the hell out of there, and it's also great for running an injector cleaning cycle, in a jury rigged kind of way. (Racist word omitted, to be politically correct)

LOL

Thanks again Doc!

Sincerely,

Refinish King

PS How about some Melingianna? I'm sure you know that means eggplant?

Inline.................

Did she start steamin' when you brazed the fitting on her due tothe fuel in the filter?

Mmmmmmmmmmm. Nuthin' better than breaded eggplant fried in some olive oil and garlic....................damn I'm hungry. Planted three types of eggplant in the garden last year but the flea beetles got the best of the plants and I only got one eggplant out of em.' Tenacious little buggers, survived a blast of Sevin AND daily baths in insecticidal soap.

Doc

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Actually:

I used a new filter, I was to chicken shit to use a used one, so I used a new Wix and a 1/8" pipe to flare fitting.

It was easy.

Refinish King

Too bad:

I'm really sorry to hear that, maybe gardening would help my nerves?

Farmer Bundy!

LOL Sincerely,

Refinish King

Just about the only thing that will get my blood pressure down for the weekend...................

Doc

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in

Ever try lady bugs? Gasoline would have killed it all (you, the eggplant, the bugs, the grass, etc..)

~KJ/TLGM

Lady bugs eat aphids, not flea beetles.

Doc

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in

I understand that they eat other bugs that move, or don't move, or haven't previously been eaten....

~KJ/TLGM

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