93 lt1 smokes on cold start??

[Raggs]

Hey guys, my 93 smokes on cold start after sitting for a week. It is fuel smoke. I replaced the fpr, no help, every injector ohm'd at 11.8 ice cold. Any ideas?? Thanks!

 

[G Winter]

I would guess that you have one or more injectors leaking down. Do you use quality fuel with good cleaners or run a good cleaner with it? The injectors may be dirty.

Glenn

 

[Hib Halverson]

Have you run the fuel pressure tests in the Factory Service Manual. If not, do that because that test will determine of you have leaking injectors or not.

 

[surfer93]

OHM the injectors with car warm OHM's should be between 14-17, be careful what injectors you buy, 92-93's are 22 lb injectors. Most people do not know that and get 24lb and I would replace all 8 at one time.

 

[Raggs]

I do run good fuel and cleaner, have not done a pressure checkyet, and just ohm'd the injestors hot and got between 12.8 and 13.1.

 

[G Winter]

Hib is saying you need to do a leak down test to see if the injectors are leaking and how fast.If you don't have the FSM have some email you the page.

Glenn

 

[kim]

If its black some its fuel if its blueish gray your valve seals are leaking.

 

[Raggs]

OK, did the leak down test. Started at 4:44 with 41psi. then, 4:47 39psi, 4:51 34psi, 4:57 28psi, 5:03 18psi, 5:07 10psi. So I am going to assume that the injectors are the problem. I know the check ball in the pump could also be bad but I'm thinking injectors.:confused

 

[G Winter]

Do you have the service manual. If so does it say how long it should hold pressure ?

Glenn

 

[surfer93]

OK, did the leak down test. Started at 4:44 with 41psi. then, 4:47 39psi, 4:51 34psi, 4:57 28psi, 5:03 18psi, 5:07 10psi. So I am going to assume that the injectors are the problem. I know the check ball in the pump could also be bad but I'm thinking injectors.:confused

That is to low, my pressure you usually stay around 30-33 psi after 30 minutes.

Take of the vacuum line on the fuel pressure regulator and see if you see fuel come out.
But, I would bet you have 1 or more bad FI's.

 

[Curious George]

If your '93 has Multec injectors (my '92 did), the 10% ethanol in today's fuel may break down the enamel wire inside the injector. I do not know if this will lead to a "leaky" injector, but in time those Multec injectors may develop problems. I replaced mine with Bosch Design lll's while diagnosing another problem.

Has anyone heard of the ethanol in today's fuel being incompatible with fuel injectors that are 15 or more years old? Is there truth in this or is it another urban legend?

CG

 

[surfer93]

If your '93 has Multec injectors (my '92 did), the 10% ethanol in today's fuel may break down the enamel wire inside the injector. I do not know if this will lead to a "leaky" injector, but in time those Multec injectors may develop problems. I replaced mine with Bosch Design lll's while diagnosing another problem.

Has anyone heard of the ethanol in today's fuel being incompatible with fuel injectors that are 15 or more years old? Is there truth in this or is it another urban legend?

CG

You know that Bosch III's are 24lb inj. and 92-93's call for 22lb.

 

[G Winter]

If your '93 has Multec injectors (my '92 did), the 10% ethanol in today's fuel may break down the enamel wire inside the injector. I do not know if this will lead to a "leaky" injector, but in time those Multec injectors may develop problems. I replaced mine with Bosch Design lll's while diagnosing another problem.

Has anyone heard of the ethanol in today's fuel being incompatible with fuel injectors that are 15 or more years old? Is there truth in this or is it another urban legend?
CG

I would have to double check to be sure but I believe my 90 owners manual says not over 5% .
There seems to be a high rate of coil failure in states with ethanol in the gas. I refuse to use the ethanol and mine failed but I don't know the history of what kind of fuel was used before I purchased it.

Glenn

 

[Curious George]

You know that Bosch III's are 24lb inj. and 92-93's call for 22lb.

Yes. I am doing PROM tuning, so I already took that into account. Thx.

CG

 

[Raggs]

FIC has bosch III for the 92-93 only. Thats what I am going to get. How did it work out for you??

 

[Hib Halverson]

OK, did the leak down test. Started at 4:44 with 41psi. then, 4:47 39psi, 4:51 34psi, 4:57 28psi, 5:03 18psi, 5:07 10psi. So I am going to assume that the injectors are the problem. I know the check ball in the pump could also be bad but I'm thinking injectors.:confused

It is likely you have one or more leaking injectors. It is, also, possible but unlikely you've got a fuel pump with a bad ball check.

Do not use injectors with a higher flow rate unless your engine is modified to the point that it needs a "bigger" injector.

Good luck.

 

[Curious George]

They seem to be working great. Much better idle and fuel mileage. The installation of them is slightly different than the OE injector... you cannot use the clips, from the OE injector, that go into the top of the fuel rail. The Bosch lll injector height and fit is maintained by a second o-ring on the bottom of the injector.

In the end it works and I have had no problems or leaks. Check out these:
Corvette, Camaro, Firebird, GTO Only - 92-93 LT 1 - 93 LTI Bosch 3 Flow Matched - Fuel Injector Connection

I know FIC is a sponsor of this forum, but there is another source for fuel injectors, at the same price as FIC; Southbay Fuel Injectors and they have a different mount for the bottom of the Bosch lll injector. FIC may have this too, but I have not seen it on their website. You may like the alternate mount, so check it out.

Sorry to bring up a competitor to a sponsor, but just trying to give people all the information they need to make an informed buying decision.

CG

 

[bucket]

Hey guys, my 93 smokes on cold start after sitting for a week. It is fuel smoke. I replaced the fpr, no help, every injector ohm'd at 11.8 ice cold. Any ideas?? Thanks!

..

uh....fuel smoke
thats an interesting theory, but i thought cold smoke was valve guides...

 

[Hib Halverson]

Hard starting in combination with black smoke after starting points at leaking injectors.

 

[CHRLDO]

FYI i've been told by an oil company employee that if you have water in your tank , the ethanol will grow algae and jam up everything in the fuel system.