1991 Airstream Classic 350 le

[bkahler]

Originally Posted by Isuzusweet

Yeah, you guys know what's coming.

Thank God I own a diesel.

Cheers
Sidekick Tony

https://www.hotrod.com/articles/hrdp...-combinations/

Tony, I see you've got your trolling motor revved up.....

[Isuzusweet]

Originally Posted by bkahler

Tony, I see you've got your trolling motor revved up.....

I at least did attach an article with possible explainations of possible causes; but yeah, couldn't resist the dig; my bad.

Cheers
Sidekick Tony

[bobmiller1]

Based on the problem described I would be looking at the pick-up coil.....Regards, Bob

[sraab928]

Thanks for the tips guys - I think I will have them replace the ICM and pick up coil just to be safe - they are both pretty inexpensive parts in the grand scheme. I really want to get this thing home so I can get to work!

[sraab928]

Originally Posted by Boom Sounds

Per previous post, if you are running out of options, i would look at the throttle body, gaskets and vacuum set up. I had a similar intermittent problem at high revs where i lost all power. I had no fault error code on the dash light reading.

I had the 220 Rochester rebuilt and replaced the vacuum lines, EGR valve etc. I am not sure what fixed the problem, but I know that particular service resolved the sag issue which I had struggled with for some time.
http://www.73-87chevytrucks.com/tech...TBISystems.pdf

It's possible that the bluetooth OBD1 diagnostics dongle might offer some additional clues. I understand that you are getting no fault lights on the dash. Has the garage monitored all the readings when it has been connected to an OBD1 computer at the same time as replicating the problem........or are they simply referring to the dash light error codes not being present?

I am no expert on the bluetooth OBD1 reader. I have played about with it and it seems to provide loads of data. Brad, Wayne or Chris Craw might be able to advise on whether it could provide you additional intelligence to aid fault finding. Obviously, there is no point in looking at this if the garage has already got the coach fully rigged up. I think Chris also had issues with his 91 TBI, I can't recall how he solved his issue, but it is probably somewhere on the site.

Good luck.

They did say they hooked up the reader and got no faults.

[bkahler]

Originally Posted by sraab928

They did say they hooked up the reader and got no faults.

My reader wasn't showing any faults either with the bad ICM.

Good luck!

[Boom Sounds]

Originally Posted by sraab928

They did say they hooked up the reader and got no faults.

I think the potential fixes which Brad and Bob are suggesting are both straightforward and low cost/effort, so sound like worth pursuing, certainly before getting into the business of a TBI/sensor rebuild. That isn't expensive in itself, but it takes time to get all the right bits and strip it down. I think some of the vacuum lines were hard to get hold of, but old new stock was kicking about on ebay. When I had the TBI rebuilt, I also took the opportunity to replace the IAC value, TPS sensor and vacumn lines so I know it is all new stuff and kept the old for spares. From memory, I think some of those can get sticky and give intermittent issues.

Detailed Service manuals here:
http://www.airforums.com/forums/f311...ml#post1895608

Suggest you check through Driveability symptoms here (section 2-12):
http://www.73-87chevytrucks.com/tech...iveability.pdf

2-12 DRIVEABILITY SYMPTOMS
HESITATION, SAG, STUMBLE
Definition: Momentary lack of response as the accelerator is
pushed down. Can occur at any vehicle speed.
Usually most severe when first trying to make
the vehicle move, as from a stop sign. May cause
the engine to stall if severe enough.

PRELIMINARY CHECKS
• Perform the careful visual/physical checks as described at start of "Driveability Symptoms,’
Section "2”.
FUEL SYSTEM
• CHECK: Fuel pressure. See "Computer Command Control,” Section "3”.
• CHECK: Throttle Position Sensor (TPS) - Check TPS for binding or sticking. Voltage should
increase at a steady rate as throttle is moved toward Wide Open Throttle (WOT).
• CHECK: MAP sensor response and accuracy. Use MAP sensor output check in "Computer
Command Control” Section "3”.
• CHECK: Water/Contaminated fuel.
• CHECK: Cannister purge system for proper operation. See "Evaporative Emission Control
n "5”.


IGNITION SYSTEM
Spark plug wires for being faulty.
Spark plugs for being fouled.
Open ignition system ground, CKT 453. See "Ignition System/EST,” Section
Ignition timing. See "Vehicle Emission Control Information” label.

ADDITIONAL CHECKS
• CHECK: For correct PROM/MEM-CAL (see Service Bulletins).
• CHECK: Generator output voltage. Repair, if less than 9 or more than 16 volts.
• CHECK: EGR valve operation. See "Exhaust Gas Recirculation (EGR) System,”

[sraab928]

Thank you for all the help. I nursed her home today and will start to dig into this more myself. Went to Napa to get a icm and coil trigger and wound up just buying a whole distributor assy so I’ll start there and see where it goes. Won’t be able to get to work on it till later next week but will keep the thread updated. Just happy she’s in my garage now.

[sraab928]

Here is a video when it’s parked under no load.

[tevake]

WOOHOO got it home, and in your garage 👍 Well done!
Inside your garage, now that's really nice.

Now you can whip it into shape at your own pace.

So you have met some of the core group here, helpful as you can see.

Keep us posted as progress unfolds. Pictures are welcome.

Cheers Richard

[Isuzusweet]

I have a 12 valve Cummins with an Allison that will solve your problems.....forever.

I think you're on the right track with the ignition.

Cheers
Sidekick Tony

[sraab928]

Originally Posted by Isuzusweet

I have a 12 valve Cummins with an Allison that will solve your problems.....forever.

I think you're on the right track with the ignition.

Cheers
Sidekick Tony

I have a habit of turning small projects into big projects. Stop giving me ideas lol.

[sraab928]

Here is a another attempt to load a video. This is under no load. Just sitting in the parking lot

https://youtu.be/cLFAi1pp-1w

[sraab928]

And another

https://youtu.be/Ovp4tX9LIyc

[bkahler]

In that last video it sounded more like it wasn't getting any gas when you revved it. Have you put any fuel additive into the tank? If not I would highly recommend Sea Foam be added and then run the engine for a while.

Does the 91 have an in-tank fuel pump or external pump? If external it would be worth a try to run a suction line from the pump to a 5-gallon can of gas mixed with Sea Foam. That will help clear the gunk out of the throttle body.

We used Sea Foam on a 310 that had sat for a long time and it helped clear up poor running.

Check out these two videos.

https://www.youtube.com/watch?v=agAWXnT4-EQ

https://www.youtube.com/watch?v=prXiQgVVnDY

Brad

[sraab928]

Originally Posted by bkahler

In that last video it sounded more like it wasn't getting any gas when you revved it. Have you put any fuel additive into the tank? If not I would highly recommend Sea Foam be added and then run the engine for a while.

Does the 91 have an in-tank fuel pump or external pump? If external it would be worth a try to run a suction line from the pump to a 5-gallon can of gas mixed with Sea Foam. That will help clear the gunk out of the throttle body.

We used Sea Foam on a 310 that had sat for a long time and it helped clear up poor running.

Check out these two videos.

Brad

The butterflies are wet - pretty sure its getting gas - yes brand new fuel pump (pretty sure its tank mounted) and filter - 13 psi to the engine. I will not have the chance to dig in into later this week - probably thursday/friday - my first step will to be to replace the distributor and eliminate that as a potential cause all together.

[Boom Sounds]

I am almost certain it has an in-tank fuel pump. I've never had mine out, but 99% certain it is there.

If the ECM is 'managing' an issue and then causing that fault, then I would expect to see it chuck up a a light on the dash, but that didn't happen with my loss of power issue. Per previous discussion, the OBD bluetooth dongle would let you monitor lots of readings relative to expected parameters. Over time, that is something you may wish to invest in. I've only undertaken basic tests on mine, but my sense is it is probably going to be money well spent at about 70 bucks. Supplier here:
https://www.ebay.co.uk/itm/16-Pin-AL...-/272138218865

More background reading.
http://tbichips.com/?page_id=351

If you get really stuck and can't resolve it yourself, I would suggest you try https://www.chevytalk.org. I had a really tricky issue with a fault code caused by an incorrect ohmage on a knock sensor. A fella there (Chevytech) managed to diagnose it for me (I was sold the wrong knock sensor despite it being off my VIN). There are some really knowledgeable people there. For the record, I am an enthusiastic amateur, although I have been at this for over ten years, so I have picked up some stuff. There are many really good people on this forum too. Several (props to Brad) who have saved me in the past....If you or anyone else does try Chevy forums, I recommend eliminating as many causes as you can first, then specify your exact set up (year, Vin, engine) and then describe the problem. They seem happy to help if people are really clear and specific.

Keep us posted with your fault finding.

Good luck

Nick

[sraab928]

The dash lights your seeing are washer fluid and parking brake. According to the shop no codes came up but I will get my code reader and and hook up myself just to be sure.

[sraab928]

The dash lights your seeing are washer fluid and parking brake. According to the shop no codes came up but I will get my code reader and and hook up myself just to be sure.

[sraab928]

Patiently waiting for me to get to work on her...