Engine dies at anything over 1500rpm

[greenjeep]

AMC 360 with TBI.

She'll idle at 6-800 rpm all day long, as soon as I give it gas it bogs down and dies if I don't let off the gas. This is a new and very annoying development.

Fuel filter, coil, cap & rotor, plugs, wires, and one of the injectors are all new. Timing recently set.

I figure a wiring issue but no idea what. Suggestions?

 

[Chevycrew]

oxygen sensor or wiring to it?

 

[Greg]

What happens if you squirt some starting fluid into the engine, while trying to rev it up? That will help you define if it's a electrical problem versus a fuel supply problem.

Sometimes fuel pumps will still work and the engine will idle, but not put out enough pressure to rev up.

That's where I'd start.

 

[greenjeep]

oxygen sensor or wiring to it?

Wiring seems fine. It came used when I bought the TBI kit from a guy on here.

What happens if you squirt some starting fluid into the engine, while trying to rev it up? That will help you define if it's a electrical problem versus a fuel supply problem.

Sometimes fuel pumps will still work and the engine will idle, but not put out enough pressure to rev up.

That's where I'd start.

I'll try that.

 

[iamsparticus]

if you give it gas does the exhaust color change? could be dumping fuel in because of a bad sensor or leaning it out way to much, what color are the spark plugs?

 

[BCGPER]

Are you by chance still running that POS AMC/Motorcraft ignition module?

 

[greenjeep]

if you give it gas does the exhaust color change? could be dumping fuel in because of a bad sensor or leaning it out way to much, what color are the spark plugs?

Exhaust comes out underneath, so I can't tell for sure, but it doesn't seem to change colors.

What do you mean what color are the spark plugs?

Are you by chance still running that POS AMC/Motorcraft ignition module?

Ummm, maybe. How can I tell?

 

[BCGPER]

Follow the distributor wires and see if they go to a silver box on the inner fender. That would be the control module. If it's there, I'd wager that's the cause. Looks expensive, but it's like $26 at Vatozone.

Ummm, maybe. How can I tell?

 

[Kiel]

I'd guess fuel pump

 

[Shawn]

I'd guess fuel pump

X2

 

[iamsparticus]

I mean if you pull a plug out is it golden brown the fuel mixture is fine, if they are black the mixture is rich and if they are white then it is too lean thats what i was getting at

 

[4x4_Welder]

Fuel filter is a good start, especially if you are using the original crap collector AMC tank. It'll mostly plug up but still pass enough fuel for idle, but won't pass enough to actually run the engine.
It'd be very odd for a DSII spark box to make this sort of issue, usually they either work or don't. I've actually used that system to retrofit both points and later feedback TFI systems with excellent results. Just don't leave the key on/ engine off with a high power coil, it'll melt the epoxy out of the box and you'll need a new one.

 

[poorboyzdreamz]

Just curiose what tbi unit is on it?

 

[toughtoy]

Are you using the stock CJ tank? If so, there is a prefilter screen on the fuel pickup tube that may be covered with gunk. Most people just take it off and depend on the fuel filter further up the fuel line. I'd check both. Also, have you checked for a vacuum leak anywhere on the engine? Usually results in a rough idle but I've seen smooth idling engines do what you're describing with a vacuum leak. Check all your small vacuum hoses and don't forget the brake booster.

 

[greenjeep]

Follow the distributor wires and see if they go to a silver box on the inner fender. That would be the control module. If it's there, I'd wager that's the cause. Looks expensive, but it's like $26 at Vatozone.

Doesn't look I have one.

I mean if you pull a plug out is it golden brown the fuel mixture is fine, if they are black the mixture is rich and if they are white then it is too lean thats what i was getting at

Good to know, thanks!

Fuel filter is a good start, especially if you are using the original crap collector AMC tank. It'll mostly plug up but still pass enough fuel for idle, but won't pass enough to actually run the engine.
It'd be very odd for a DSII spark box to make this sort of issue, usually they either work or don't. I've actually used that system to retrofit both points and later feedback TFI systems with excellent results. Just don't leave the key on/ engine off with a high power coil, it'll melt the epoxy out of the box and you'll need a new one.

Not the original AMC tank and a new inline fuel filter.

Just curiose what tbi unit is on it?

Not sure, got it used.

Are you using the stock CJ tank? If so, there is a prefilter screen on the fuel pickup tube that may be covered with gunk. Most people just take it off and depend on the fuel filter further up the fuel line. I'd check both. Also, have you checked for a vacuum leak anywhere on the engine? Usually results in a rough idle but I've seen smooth idling engines do what you're describing with a vacuum leak. Check all your small vacuum hoses and don't forget the brake booster.

TJ aftermarket tank. Vacuum lines seem ok.

 

[greenjeep]

What happens if you squirt some starting fluid into the engine, while trying to rev it up? That will help you define if it's a electrical problem versus a fuel supply problem.

Sometimes fuel pumps will still work and the engine will idle, but not put out enough pressure to rev up.

That's where I'd start.

I'd guess fuel pump

X2

WE HAVE 3 WINNERS!!

New fuel pump, and fired right up and ran great!

Thanks everyone!!

 

[Greg]

 

[iamsparticus]