Help Needed With Cold Start Issues..

goat19642004 · January 14, 2008

My 1999 Tahoe with 5.7 engine does not want to start when temps. drop below 40 degrees. The engine cranks without any signs of firing then finally stumbles to a stable idle. When temps are above 40 degrees it starts without any hesitation. I checked the fuel pressure and it is 62 psi when the key is on and 55 psi while running. I also monitored the pressure after I shut the key off and noticed no drop in pressure after 1/2 hour.

The distributor and wires were replaced along with plugs, fuel filter and air filter. The truck has 86,000 miles on it and also has a Wait for me tune.

Can anybody point me in another direction?

GMTRUCKTECH · January 14, 2008

Assuming your have fuel and spark I would unplug your cranksensor and check the connector cavity and make sure the pins are good and tight. The cranksensor is located behind the crank balancer in the front of the oil pan. It's a shot in the dark but there is not many things that will not allow the motor to start when it has fuel and spark.

minibike132 · January 15, 2008

I was working with you on another thread. Do me a favor(maybe you too) I know the cap and rotor is new but take the cap off and take a look, see if it still looks new.

goat19642004 · January 15, 2008

Thanks for the input guys. I checked the crank sensor connector tonight, all looks good in the connector and pins are tight with no corrosion. I also pulled the cap and checked the rotor and contacts. They look new with no signs of arcing. I also plugged in my OBII scanner and checked for any misfire history, IAT temp readings, coolant sensor, etc. All looked well and functioning.

It seems strange that this problem only happens when its gets below 40 degrees outside. When its warm outside she starts with 1/2 a crank. What system(s) control extra fuel during a cold start situation? The truck acts like the old carb days when your choke was stuck open...

GMTRUCKTECH · January 15, 2008

Here's some bull that MAY help if anything some good info.

Subject:No/Hard/Slow Start, Backfire/Kickback (Replace Crankshaft Position Sensor) #00-06-04-014 - (03/28/2000)

Models:1999-2000 Cadillac Escalade

1995-2000 Chevrolet and GMC S/T Models

1996-2000 Chevrolet and GMC C/K, M/L , G, P Models

1996-2000 Oldsmobile Bravada

with 4.3 L, 5.0 L, 5.7 L or 7.4 L Engine (VINs W, X, M, R, J -- RPOs L35, LF6, L30, L31, L29)

Condition

Some customers may comment on one or more of the following conditions:

• Backfire during crank/start

• "Kickback" during crank/start

• "No" start

• "Slow" or "hard" start/crank

• "Grinding" or unusual noises during crank/start

• Cracked or broken engine block at the starter boss

• Broken starter drive housing

• Broken starter ring gear on flywheel

• Any combination of the above

Cause

A condition may exist that allows the crankshaft position sensor to command up to 50 extra degrees of spark advance during engine cranking only. This in turn exposes the engine to higher than normal cylinder pressures which may result in an inoperative condition to the starter drive housing, the engine flywheel starter ring gear, or the engine block at the outside edge of the starter boss.

Correction

Inspect for a stored powertrain DTC code P0338. This DTC will NOT illuminate the "Service Engine Soon" light. If this code is stored, the Crankshaft Position Sensor, P/N 10456607, MUST be replaced and the remaining components inspected for damage (engine block at the starter boss, the starter drive housing, and the engine flywheel starter ring gear).

Notice: When DTC code P0338 is set, failure to replace the Crankshaft Position Sensor could result in repeated inoperative conditions of the starter or flywheel.

Important: Some flywheel wear is normal; broken or missing teeth and/or cracks, are not normal.

Parts Information

Parts are currently available from GMSPO.

Warranty Information

For vehicles repaired under warranty, use:

Labor Code

Description

Labor Time

J4355

Sensor, Crankshaft Position - Replace

Use Published Labor Time

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.

WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION

© Copyright

Subject:Special Policy Adjustment-Sequential Central Port Fuel Injection (SCPI) Failures in California Only (YF5 Emission Equipped) #99066G - (11/05/2003)

Models:Certain 1996, 1997, 1998, 1999, 2000, 2001, 2002 S/T, M/L, C/K, G, P, W4/NPR Trucks and 2003 NPR Trucks

Equipped with 4.3L (RPO L35-VIN Code W or RPO LF6-VIN Code X), 5.0L (RPO L30-VIN Code M) or 5.7L (RPO L31-VIN Code R) Engine and California Emission Equipped (RPO YF5)

This bulletin is being revised to emphasize to Dealers the important of replacing the engine SCPI fuel assembly with the new MFI fuel assembly if the vehicle has already received an injector cleaning. Please discard Special Policy Bulletin Number 99066F, dated March, 2003.

Condition

Some owners of 1996, 1997, 1998, 1999, 2000, 2001 and 2002 model year S/T, M/L, C/K, G, P and W4/NPR trucks and 2003 NPR trucks that are registered in California, equipped with 4.3L (RPO L35 and VIN Code W or RPO LF6 and VIN Code X), 5.0L (RPO L30 and VIN Code M) or 5.7L (RPO L31 and VIN Code R) engine, and California emissions (RPO YF5), may experience a Service Engine Soon light, misfire, rough idle or hard start due to a deposit build up on the Sequential Central Port Injector (SCPI) poppet valve(s). The deposit build up may cause injector poppets to stick closed. Fuels used in California have been found to interact with the SCPI system to cause the deposits.

Special Policy Adjustment

This special policy covers the SCPI failure condition described above for a period of ten (10) years or 200,000 miles, whichever occurs first, from the date the vehicle was originally placed in service, regardless of ownership.

The repairs will be made at no charge to the owner. This special policy applies ONLY to repairs requiring SCPI system servicing and/or injector cleaning and/or MFI assembly replacement of the SCPI system. The customer should not be charged for performing a system check when it is determined that the SCPI system is not the cause of a customer complaint (labor operation T5532 is provided to submit claims for such system checks). Any additional necessary diagnosis and repairs that are not related to the SCPI condition are NOT covered by this special policy. The customer should be informed that any further service that is not covered by new vehicle warranty will not be covered by this policy.

Vehicles Involved

Involved are certain 1996, 1997, 1998, 1999, 2000, 2001, 2002 S/T, M/L, C/K, G, P, W4/NPR and 2003 NPR model vehicles registered in California, equipped with 4.3L engine (RPO L35-VIN Code W or RPO LF6-VIN Code X), 5.0L engine (RPO L30-VIN Code M) or 5.7L engine (RPO L31-VIN Code R) and California emissions (RPO YF5). This Special Policy covers all vehicles within these model years, with these engine and emission RPOs.

Parts Information

Parts required to complete this Special Policy are to be obtained from General Motors Service Parts Operations (GMSPO). Please refer to your "involved vehicles listing" prior to ordering parts. Normal orders should be placed on a DRO=Daily Replenishment Order. In an emergency, parts should be ordered CSO=Customer Special Order.

Part Number

Description

Qty/ Vehicle

12345382

Sealant, Thread, Med. Strength (6 ML)

As required

TBD*

Cleaner, Top Engine (24 ml)

If required and available

TBD*

Cleaner, Top Engine (15 oz)

24 ml (12346535 size alternative)

12345104

Cleaner, Port Fuel Injector (20 oz)

If required

15050573

Asm-Fuel Tank Fill Pipe (97-99 M/L Van)

1, if required

15747585

Asm-Fuel Tank Fill Pipe (99 C/K E63 w/o AC7)

1, if required

15747588

Asm-Fuel Tank Fill Pipe (99 C/K E62 w/o AC7)

1, if required

12568332

Assy, V6 Fuel Injector

1, if required

88894355

Bracket, V6

1, if required

17113215

Kit, V6 Seal

1, if required

93441235

Assy, V8 Fuel Injector

1, if required

93442096

Bracket, V8

1, if required

17113206

Kit, V8 Seal

1, if required

*Top engine cleaner part number 12346535 and 1050002 are no longer California compliant. California dealers will be notified via a DCS message when new alternative cleaner part numbers become available.

Important: Isuzu Parts Ordering: In order to comply with the 10-digit Isuzu part numbering system, Isuzu deaelrs must add an "8" to the beginning and a "0" to the end of the listed 8-digit part numbers when ordering parts through AIPDN.

Customer Notification

Customers will be notified of this Special Policy on their vehicles by General Motors (see copy of typical customer letter included with this bulletin-actual divisional letter may vary slightly).

Service Procedure

System Check

Use strategy-based diagnoses listed in the front of the Driveability and Emissions section of the Service Manual. If the SCPI system is operating properly, inform the customer that the vehicle does not have the condition listed in the owner letter. If poor driveability conditions persist, inform the customer that any further diagnosis and repairs will be at their expense if the vehicle is outside the parameters of the New Vehicle Warranty.

SCPI Injector Cleaning Procedure

If diagnosis leads to sticking poppet nozzles, first check GMVIS to determine if the vehicle had a previous claim for injector cleaning under labor claims J5645, T5534 or T5540. If any of these three repair claims are listed, do not clean the injectors, but rather replace the engine SCPI fuel assembly with the MFI fuel assembly. If none of these three repair claims is listed, use the service procedure from Service Bulletin 00-06-04-003B to clean the SCPI poppet nozzles. Please note that the service bulletin term for SCPI is Central Sequential Fuel Injection (CSFI), but is referring to the same fuel system assembly.

SCPI Fuel Tank Fill Pipe Assembly for 1997-99 M/L Van and 1999-some 2000 C/K Truck; with 4.3L, 5.0L, 5.7L engines and built prior to listed VIN/Production dates on Service Bulletin 00-06-04-018

If diagnosis leads to sticking poppet nozzles on these models, use the service procedure from Service Bulletin 00-06-04-018 to replace the fuel tank fill pipe assembly, if this procedure has not been performed previously. Previous service procedure can be verified by checking GMVIS for Labor Operation L1065 on M/L trucks with replacement part number 15050573; or Labor Operation L1065 on C/K trucks with replacement part numbers 15747585 or 15747588.

Correction

If, AFTER cleaning the SCPI poppet nozzles, the normal service manual diagnosis still indicates that the SCPI is the cause of the customer complaint, or if the injectors have previously been cleaned and the vehicle has again experienced sticking poppet nozzles, refer to Service Bulletin 00-06-04-003B and replace the SCPI fuel assembly with the MFI fuel assembly. Please note that the service bulletin term for SCPI is Central Sequential Fuel Injection (CSFI), but is referring to the same fuel system assembly.

Claim Information

For vehicles repaired under this special policy, submit a claim with the information indicated below.

Repair Performed

Part Count

Part No.

Parts Allow

CC-FC

Labor Op

Labor Hours

System Check-No SCPI Repair Needed

NA

NA

NA

MK-95

T5532

0.0-0.3 hr

Clean Fuel Injectors per Service Bulletin 00-06-04-003B:

--

--

*

MK-95

T5540

--

S/T Truck

--

--

--

--

--

1.3 hrs

M/L Truck, P Truck, W4 Truck

--

--

--

--

--

1.0 hr

C/K Truck

--

--

--

--

--

1.3 hrs

G Van

--

--

--

--

--

1.5 hr

Replace Fuel Tank Fill Pipe Asm.

1

--

*

MK-95

T5557

1997-99 M/L Van

0.8**

1999 and some 2000 C/K Truck

Use published labor operation time

Replace SCPI fuel system with a new MFI fuel system per Service Bulletin 00-06-04-003B

--

*

MK-95

T5576

1.4 hrs

M/L Van only

add 0.2 hr

* -- The "Parts Allowance" should be the sum total of the current GMSPO Dealer Net price plus applicable Mark-Up for SCPI/CSFI parts, fuel tank filler hose and gasket needed to complete the repair.

** -- This labor time is a change to the current Labor Time Guide. The next update of the Labor Time Guide will include this change.

<A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=1400638&psdid=96&evc=sm#ss8-1400638">

Customer Reimbursement

Customer requests for reimbursement are for any previously paid repairs to, or replacement of, the Sequential Central Port Fuel Injection (SCPI) system. Repairs must have occurred within 10 years of the date the vehicle was originally placed in service, or 200,000 miles, whichever occurs first. The requests are to be submitted within two (2) years of the date on which the repair was paid or within two (2) years of the date of this Special Policy Bulletin, whichever is greater.

When a customer requests reimbursement, they must provide the following:

• Proof of ownership at the time of the repair

• Original paid receipt confirming the amount of the unreimbursed repair expense(s) (including Service Contract deductible), a description of the repair, the date repaired, and the person or entity performing the repair

Customers from the State of California must submit requests for reimbursement directly to (divisions) per instructions in the owner letter.

If the work was done by someone other than a GM dealership, the amount of reimbursement will generally be limited to the amount that the repair would have cost GM to have it completed by a GM dealership.

April, 2003

Dear General Motors Customer:

As the owner of a 1996, 1997, 1998, 1999, 2000, 2001, 2002 model year S/T, M/L, C/K, G, P, W4/NPR truck or 2003 model year NPR truck that is registered California, equipped with a 4.3L V6, 5.0L V8 or 5.7L V8 engine, and California emissions, your satisfaction with our product is very important to us. Your vehicle was provided with a new vehicle warranty, which covers certain parts of your vehicle for a specific period. These warranties are of considerable value to you if you should experience problems with your vehicle.

This letter is intended to make you aware that some owners of 1996, 1997, 1998, 1999, 2000, 2001, 2002 model year S/T, M/L, C/K, G, P, W4/NPR trucks and 2003 model year NPR trucks that are registered in California, equipped with 4.3L V6, 5.0L V8 or 5.7L V8 engine, and California emissions, may experience a Service Engine Soon light, misfire, rough idle or hard start due to a deposit build up on the Sequential Central Port injector (SCPI) poppet valve(s). The deposit build up may cause injector poppets to stick closed. Certain fuels have been found to interact with the SCPI system to cause the deposits.

This is not a recall. Do not take your vehicle to your General Motors dealer as a result of this letter unless you believe that your vehicle has the condition as described above.

What We Have Done

To address the above-mentioned condition, General Motors is providing special warranty coverage to owners of applicable vehicles registered in California. If the SCPI system failure condition occurs on your 1996, 1997, 1998, 1999, 2000, 2001, 2002 S/T, M/L, C/K, G, P, W4/NPR truck or 2003 model year NPR trucks within 10 years of the date your vehicle was originally placed in service or 200,000 miles, whichever occurs first, the condition will be repaired for you at no charge . Other conditions that may cause similar or different driveability complaints, or cause a Malfunction Indicator Light illumination, that are not a result of SCPI system failure are NOT covered by this special policy. However, you will not be charged for performing a system check when determining that the SCPI system is not the cause. Any repairs made outside the normal warranty coverage due to other conditions would be your responsibility, if you elect to have your dealer provide the service.

What You Should Do

Repairs and adjustment qualifying under this special coverage must be performed by a <Division> dealer. You may want to call the service department at the dealer to find out how long they will need to have your vehicle so that you may schedule the appointment at a time that is convenient for you. This will also allow your dealer to order parts if they are not already in stock. Keep this letter with your other important glovebox literature for future reference.

Reimbursement

If you have already paid for some or all of the cost to have the SCPI fuel system repaired or replaced, and you have not received reimbursement under a Vehicle Service Contract, and the in-service time and mileage was less than 10 years and 200,000 miles, you should write to your (divisional specific address) to seek reimbursement. Please provide your original paid receipts or invoices verifying the repair, the amount charged, proof of payment, the date of payment of those charges and proof of ownership of the vehicle at the time of the repair. This information must be provided within two (2) years of the date on which you paid for the repair or within two (2) years of the date of this Special Policy Bulletin, whichever is greater.

If the work was done by someone other than a GM dealership, the amount of reimbursement will generally be limited to the amount that the repair would have cost GM to have it completed by a GM dealership.

If you have any questions or need any assistance, just contact your dealer or the appropriate Customer Assistance Center at the number listed below:

Division

Number

Deaf, Hearing Impaired, or Speech Impaired*

Cadillac

1-800-458-8006

1-800-833-2622

Chevrolet

1-800-222-1020

1-800-833-2438

GMC

1-800-462-8782

1-800-462-8583

Oldsmobile

1-800-442-6537

1-800-833-6537

Isuzu Medium Duty

1-800-862-4389

* Utilizes Telecommunication Devices for the Deaf/Text Telephones (TDD/TTY)

We are sorry for any inconvenience you may experience; however we have taken this action in the interest of your continued satisfaction with our products.

General Motors Corporation

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.

WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION