injector problem or coil pack problem?

[ZZZZZR1]

hey guys,

Car started to "stumble" @ 35mph in a big way yesterday....

Lost power and seemed like the motor couldn't breath. I kept feeding the gas and it knocked more & more. Then stalled. In order to get it started I had to push the gas and white smoke would come out in 1st / 2nd gear. 3rd gear on, no white smoke (motor had minimal power).

Drove 150 miles and went thru 13 gallons of gas. Car did idle for probably 20min durring that time.

What is the best way to see if the injectors are bad and if there is a coil pack problem.

thanks!

David

[GOLDCYLON]

hey guys,

Car started to "stumble" @ 35mph in a big way yesterday....

Lost power and seemed like the motor couldn't breath. I kept feeding the gas and it knocked more & more. Then stalled. In order to get it started I had to push the gas and white smoke would come out in 1st / 2nd gear. 3rd gear on, no white smoke (motor had minimal power).

Drove 150 miles and went thru 13 gallons of gas. Car did idle for probably 20min durring that time.

What is the best way to see if the injectors are bad and if there is a coil pack problem.

thanks!

David

David what year car how many miles (94)???? Does it have stock injectors its sound like injectors all the way and if I may suggest you buy FU2 injectors which are RCs right away. He has a slightly used set for $700 plus shipping (He upgraded to a stroker motor) which is a steal I paid $1250 for mine last year!!!!

http://www.zr1netregistry.com/forum/showthread.php?t=6320

Either way I suggest you replace the coil packs as your in for a plenum pull anyway. I bought set of 4 off of Ebay last year for $150. Easiest way is to see if your throwing some codes on a scanning tool. Did your SES light come on in the DIC?

[-=Jeff=-]

David what year car how many miles (94)???? Does it have stock injectors its sound like injectors all the way and if I may suggest you buy FU2 injectors which are RCs right away. He has a slightly used set for $700 plus shipping (He upgraded to a stroker motor) which is a steal I paid $1250 for mine last year!!!!

http://www.zr1netregistry.com/forum/showthread.php?t=6320

Either way I suggest you replace the coil packs as your in for a plenum pull anyway. I bought set of 4 off of Ebay last year for $150. Easiest way is to see if your throwing some codes on a scanning tool. Did your SES light come on in the DIC?
:iamwithst

[jonszr1]

there is another option on injectors ficinjectors, ask for jon bosch type 2 or 3 depending on your year 380 to your door . they are flow mat5ched and have a 3 yr warrenty . i have a set in my 92 and they are awsome .

[Paul Workman]

hey guys,

Car started to "stumble" @ 35mph in a big way yesterday....

Lost power and seemed like the motor couldn't breath. I kept feeding the gas and it knocked more & more. Then stalled. In order to get it started I had to push the gas and white smoke would come out in 1st / 2nd gear. 3rd gear on, no white smoke (motor had minimal power).

Drove 150 miles and went thru 13 gallons of gas. Car did idle for probably 20min durring that time.

What is the best way to see if the injectors are bad and if there is a coil pack problem.

thanks!

David

White "smoke", stumbling and dying, and loss of power sounds more like a head gasket to me. BTDT too many times myself. Pull the plugs and have a look-see. If you have a cylinder or two where the plug(s) are all white (or even have antifreeze on them!), whereas the rest are normal...I'd say gasket "fer sher". Also, if the dipstick is coated w/ something that looks like a chocolate milk shake...you have antifreeze in the crank case. Boy! I'm just full of good news, huh?

Hope I'm wrong 'bout the coolant leaks... Hope it is something simple.

P.

[XfireZ51]

Coolant leak may not be head gasket. Do as Paul suggests and see if
any plugs look wet or washed. Pull plenum. Do coolant pressure check.
My leak showed up between IH and cylinder head on #4 primary runner.

[ZZZZZR1]

wow....

Thanks for all the info guys! A fellow Z brother is going to help out tomorrow and hopefully figure this out!

Awesome info :thumbsup:

[QB93Z]

To add some more information. The white "smoke" from the exhaust smelled like raw gasoline. I helped David pull three plugs and they looked fine.

No sign of coolant loss from the expansion tank.

When we pulled plug wires, all wires caused the choppy idle to get worse except #1. There was no change in the idle when #1 wire was pulled. The plug wire for #1 when pulled, sparked to the engine with a healthy spark.

We plan on doing a fuel leakdown test next.

Any other ideas?

Jim

[-=Jeff=-]

I am sticking with Injectors as my thought,, my 90 did the SAME thing this past summer

it was injectors

[GOLDCYLON]

My moneys on Injectors as I originally stated, And I suggest replacing the coils for good measure while under the plenum as stated as well. White smoke is indicative of Raw fuel as well. The additional information of fuel smell as adds weight to my initial conclusion. I would be interested to see what the fuel pressure was like at the rail and how long the pressure holds. That should nail down the injector consensus as well. And rule out fuel pump issues as well. Just a thought. GC

And before Franks RC Injectors slip away again Jim I suggest the owner gets Jiggy wit it pretty darn fast before they are NLA. (you can ask me the story of why they are available again if you wish!) Anddd.. Frank is dontating the cash for those 100% to our injuried Z brother... Which mean to me several things. Frank is a classy guy. ZR-1 Owners rock and I love the brotherhood.

[Aurora40]

How was the fuel pressure? What did the #1 plug look like? You might also check the FPR's vacuum line to see if there's gas in it.

You can buy a spark tester for like $10, they sort of look like a spark plug but with a weird end.

I wouldn't think only one cylinder down would be as bad as the symptoms you are describing.

[Jim Nolan]

If it is the injectors they must be in very bad condition. When I pulled mine for the porting my secondaries were very corroded, but my ZR1 ran very good and never burped once.

[GOLDCYLON]

If it is the injectors they must be in very bad condition. When I pulled mine for the porting my secondaries were very corroded, but my ZR1 ran very good and never burped once.

Mine were rusty as hell as well. Wont happen with RCs as they have a stainless steel insert.

[ZZZZZR1]

Injector #1 was bad...

Jim said from day 1 what it was and sure enough!

:worship:

:thumbsup::thumbsup::thumbsup::thumbsup:

[GOLDCYLON]

Injector #1 was bad...

Jim said from day 1 what it was and sure enough!

:worship:

:thumbsup::thumbsup::thumbsup::thumbsup:


Actually I did in post #2 but hey its up and running. But I would still my FUs complete set

[FU]

But I would still my FUs complete set
Thanks for the mention Daryll :wave:

:mrgreen::mrgreen: Plus all the proceeds go to a great cause.And if you have a a 90-92 , your going to need them sooner or later .

[QB93Z]

Follow up on the problem:

The symptoms were: loss of power, rough, stumbling operation, stalling at idle, hard to start, and white smoke at the exhaust that smelled like gasoline.

Pulling spark plug wires showed no change in rough idle for #1 plug wire. All other plug wires made the idle worse.

Fuel leak down test: ignition key to on, fuel pressure steady at about 50 psi. Ignition key to off, fuel pressure immediately dropped to zero.

Pulled the Plenum. Turn the ignition key to on, observed fuel squirting from #1 primary injector.

We replaced the bad #1 injector with a used injector to get the car running again.

Jim

[Jagdpanzer]

Follow up on the problem:

The symptoms were: loss of power, rough, stumbling operation, stalling at idle, hard to start, and white smoke at the exhaust that smelled like gasoline.

Pulling spark plug wires showed no change in rough idle for #1 plug wire. All other plug wires made the idle worse.

Fuel leak down test: ignition key to on, fuel pressure steady at about 50 psi. Ignition key to off, fuel pressure immediately dropped to zero.

Pulled the Plenum. Turn the ignition key to on, observed fuel squirting from #1 primary injector.

We replaced the bad #1 injector with a used injector to get the car running again.

Jim

Well done skipper, I hear by promote you to honorary Engineman

[HIZNHRZ]

Here's the link from Marc Haibecks website for isolating bad fuel injectors. All you need is a digital multimeter and the ability to follow the instructions. Bob and I used it a little over a year ago. It gives you the ability to determine if any others are on the way out.

http://www.zr1specialist.com/HAT%20Web/articles/Measuring%20Fuel%20Injector%20Resistance%20with%20 the%20Plenum%20in%20Place.pdf

[QB93Z]

Here's the link from Marc Haibecks website for isolating bad fuel injectors. All you need is a digital multimeter and the ability to follow the instructions. Bob and I used it a little over a year ago. It gives you the ability to determine if any others are on the way out.

http://www.zr1specialist.com/HAT%20Web/articles/Measuring%20Fuel%20Injector%20Resistance%20with%20 the%20Plenum%20in%20Place.pdf

Thanks for the link. The injector failure that occurred was mechanical (stuck open), so it did not have an electrical problem that we could have measured.

Jim

[Sgreg]

hey guys,

Car started to "stumble" @ 35mph in a big way yesterday....

Lost power and seemed like the motor couldn't breath. I kept feeding the gas and it knocked more & more. Then stalled. In order to get it started I had to push the gas and white smoke would come out in 1st / 2nd gear. 3rd gear on, no white smoke (motor had minimal power).

Drove 150 miles and went thru 13 gallons of gas. Car did idle for probably 20min durring that time.

What is the best way to see if the injectors are bad and if there is a coil pack problem.

thanks!

David

Just a suggestion, but I would check your fuel pressure. May be about to lose a pump. Then look at injectors.