Really need your help (stumble when throttle is applied)

[MiniSimp]

The answer was the fuel pump, the symptoms are the following:

Ok, so to update on the progress (and lack of) so far:

Ok, so engine is throwing code 11:
Short circuit is check connector terminal T with the air conditioning switch ON or throttle switch (IDL) point OFF - defective air conditioner switch. Throttle Position Sensor (TPS) circuit, Throttle Position Sensor (TPS) or Electronic Control Unit (ECU) No longer throws this code.

Engine threw code 2 and 6 No longer throws this code

Will not idle below 1300 RPM's After setting timing, Idle is good.

When light throttle is applied it will go to 5K RPM's Actually 3100RPMs is the highest I can get it to go.

When middle/full throttle is applied engine RPM's drop and engine sputters down to 500 RPM's and dies

TPS sensor (2nd one) is good and adjusted

Timing is set to 5*B

Idle is set to 765

There is no air leak from the air box to the throttle body. (air tube is currently wraped in Duct tape.

The AFM tested good with a meter. (AFM has not been modified)

Air box flap moves smooth

Throttle body is clean.

Fuel flow is good before and after the fuel filter (fills 18oz in 15 seconds)

Cold Start injector was replaced with a used one and now works. (fixing the hard start problem)

The ECU tested fine with a meter (except brake switch signal) picking up ECU to swap, just in case.

Spark plugs, wires, dist cap, air filter, O2 sensor are all new.

Igniter tested good with a meter.

There is a light backfire in the intake.

The exhaust is not clogged.

All ground wires are connected.

Tire pressure is 17lbs.

Video with audio:

[Duffil]

I've got a carb Ill sell you.

[Duffil]

Unfortunately, I don't think I know enough about the EFI to be of much help. 



If you unplug the TPS, does it change the way it runs? It is pretty rare, but do you have a spare ECU to swap in and check? The only other thing I could think of would be a sticky MAF lever or bad MAF sensor, though I would think it should throw a code if that were the case.

If you want to screw with it tomorrow or sunday, those are my days off.

[*** YELLER ***]

maybe you should come up here and go thru this stuff and see if you need any of it 

[Duffil]

maybe you should come up here and go thru this stuff and see if you need any of it 

see if the numbers on you ECUs match, let him borrow it for testing.

[Lady Di]

OMG! WHAT?? MINI!!!

[Ramrod]

AIR LEAK! AIR LEAK!

[Duffil]

OMG! WHAT?? MINI!!!

don't worry.  He'll be there even if it's behind my truck holding a tow rope on a skateboard.


Well, that's better than riding in a jeep, right?

[Duffil]

AIR LEAK! AIR LEAK!

I thought about that, but it should run worse at idle (higher vacuum) than at RPM.

[Lady Di]

don't worry.  He'll be there even if it's behind my truck holding a tow rope on a skateboard.


Well, that's better than riding in a jeep, right?

  Unless one is welding his rear end back under his rig 

(OK so we're not really a jeep)

[*** YELLER ***]

from toy86 on Pirate


now that ive watched the video it sounds 100% like my 86 when there was a leak in the air intake tube. It happened 2 seprate times and both were just like that. Inspect for leaks, tighten clamps and if that doesnt work either get a new intake hose or wrap the one you have in duct tape (what I did before the other steps) really it solved everything

[Duffil]

AIR LEAK! AIR LEAK!

I thought about that, but it should run worse at idle (higher vacuum) than at RPM.

or do you mean air leak, as in upstream of the tps...as opposed to vacuum.

[Duffil]

from toy86 on Pirate


now that ive watched the video it sounds 100% like my 86 when there was a leak in the air intake tube. It happened 2 seprate times and both were just like that. Inspect for leaks, tighten clamps and if that doesnt work either get a new intake hose or wrap the one you have in duct tape (what I did before the other steps) really it solved everything

pulls in outside air, but the AFM stays in the same place, thus no more fuel.  get a can of carb cleaner and go to town.

[*** YELLER ***]

  get a can of carb cleaner and go to town.

Where does he go to town at

[IronClad]

yep air leak

[Ramrod]

just like I wrote on pirate first tighten all the clamps on the plastic intake hose.  after that look all around on the hose for cracks or holes.  Everyone ive seen (3-4) was in the first section where its kinda like a snake bend.  If you dont see anything i'd still just wrap it tight with ductape for the hell of it and see if it works.  thats what I did with mine and geno did on his at the rubicon

[IronClad]

yeepers.. i had the same problem.. wrapped my entire intake tube with duct tape and whammo  good as new

[Duffil]

Where does he go to town at

9th st in modesto.  place called the Brave Bull.  Or at Faces in Sacto.

[MiniSimp]

Thanks guys!
I'll check the intake right now.

[Tallchevy]

pulls in outside air, but the AFM stays in the same place, thus no more fuel.  get a can of carb cleaner and go to town.

I know the throttle body is clean cause I cleaned it before he got it. I've ran my 22RE with the intake hose off so I can spray cleaner through the throttle body while it running & it sounds just like yours. I agree, check the intake hose from the air cleaner to the throttle body.

If that don't work, I have a test ECU  from an 85 you can BARROW 

[Willy Mammoth]

Just wrap the whole motor in duct tape that should do it.

[*** YELLER ***]

9th st in modesto.  place called the Brave Bull.  Or at Faces in Sacto.

why do you know where that is

[Duffil]

the owners are NAPA customers.

[*** YELLER ***]

the owners are NAPA customers.

sure whatever 

[Tice]

Sounds just like both times my fan went into my intake tube. 

[BigMike]

I just read this thread. I would check the air box. Have you even opened up the top cover before? If so, then how did you reseal it? Do you have any extra air boxes laying around? Check if they are the square D shape or the round D shape.

If you've got an air leak of any sizeable mention, then it would either not start up, or it would have a very sporadic idle.

Regards,
BigMike

[MiniSimp]

Ok, hose wrapped in duct tape did not work.
I'll check the air box tomorrow, along with anything else you guys suggest between now and then.

Thanks again.

[85xcab]

Won't the older ecm's store code 11 if you run the engine with the test connector jumped?

[MiniSimp]

Won't the older ecm's store code 11 if you run the engine with the test connector jumped?

I have run it with it connected. Will check that tomorrow.

[BigMike]

If you are looking for vacuum leaks, then with the engine idling, fill a spray bottle with something flammable, such as brake cleaner, and start squirting once-at-a-time around all intake hoses and vacuum lines, anywhere where vacuum exists at an idle including the line to your brake booster.

If a leak exists, then it will suck the vapors (from the mist you just sprayed) into the intake system and the idle will surge +500 rpm or so and then quickly fall back down to its previous idle.

The larger the vacuum leak the greater the RPM change during this procedure.

For any legal matters, my disclaimer to you is not to worry too much about the fumes from your spray bottle. I know you wouldn't be running your engine in an area that is not well ventilated. The flash point of brake cleaner is safe enough that you could spray it on to your cast exhaust manifold while it is running and although I do not recommend this, it will not cause any problems.

Regards,
BigMike