1997 Chevy Tahoe fuel injection

Tiny
KERRYM
  • MEMBER
  • 1997 CHEVROLET TAHOE
  • V8
  • 4WD
  • AUTOMATIC
  • 170,000 MILES
The Tahoe ran fine and then quit without warning at highway speed.
The fuel pump DOES start and runs for 2 seconds when the ingnition is turned on. (I have replaced that twice before). The engine fires and kicks over as you would expect with a squirt of starter fluid. I found that the fuel pressure was dropping off rapidly after the fuel pump turned off, so I have replaced the fuel pressure regulator. It now holds good pressure for over 1 hour. QUESTION: How can I determine if the fuel spider is receiving the electrical signials that are required? What tests or diagnostic tools are required?
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Saturday, November 8th, 2008 AT 5:48 PM

4 Replies

Tiny
RASMATAZ
  • MEMBER
Lets try this first-inspect/test the oil pressure sending unit. The fuel pump primes the system for 2secs-that's it-when the engine fires up the OPSU powers the pump-
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Saturday, November 8th, 2008 AT 6:11 PM
Tiny
KERRYM
  • MEMBER
I understand that if the oil pressure sending unit was not closing the fuel pump contacts, the pump would not keep the fuel pressure up. However, after cranking the engine for about 10 seconds, I still have fuel pressure. I do not need to re-energize the ignition to get it.
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Saturday, November 8th, 2008 AT 6:33 PM
Tiny
IMPALASS
  • EXPERT
Hello

Well you need scan equipment that can turn on and measure the out put of the various items.

When you say it holds good pressure now does that also mean it runs.

However, based off what you say, please go to Auto Zone or O'Reilly's and for free they can pull the codes to the car. Most important. Once they check your codes, if they find something and you don't get it fixed and need to get back with us, please make sure you tell us exactly what the code was, number and all. Example, if the code was E0568 O2 Sensor bad. Then make sure you give us all of that. While there for free also they can bring their tester out and check your battery, alternator and starter. This way we can see if any codes are dropping.

Next, I have attached a TSB that talks about the crankshaft sensor can cause a no start, hesitation etc for your review.

File In Section: 06 - Engine/Propulsion System
Bulletin No: 00-06-04-014
Date: April, 2000
TECHNICAL
Subject:
No, Hard, or Slow Start, Backfire or "Kickback" During
Crank/Start, "Grinding" or Unusual Noises During Crank, DTC P0338
(Replace Crankshaft Position Sensor)
Models:
1999-2000 Cadillac Escalade
1995-2000 Chevrolet and GMC SIT 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.

I have also attached what it does but we need to see if any codes are thrown.

DESCRIPTION
The Crankshaft Position (CKP) Sensor is located in the front engine cover and is perpendicular to the crankshaft target wheel. The air gap between the sensor and the wheel is preset and not adjustable. The target wheel has three slots 60 apart and is keyed to the crankshaft. As the target wheel rotates, the slots passing by the sensor create a change in the magnetic field of the sensor which results in an induced voltage pulse. One revolution of the crankshaft results in three pulses (3x signal). Based on these pulses, the VCM is able to determine crankshaft position and engine speed. The VCM then activates the fuel injector and provides a spark to the Distributor. The relation between the crankshaft position sensor and the target wheel is crucial. The sensor must be exactly perpendicular to the target wheel with the correct air gap.

OPERATION
The crankshaft position sensor provides the VCM with crankshaft speed and crankshaft position. The VCM utilizes this information to determine if an engine Misfire is present. The VCM monitors the Crankshaft Position Sensor (CKP) sensor for momentarily drop in crankshaft speed to determine if a misfire is occurring. When the VCM detects a misfire, a Diagnostic Trouble Code (DTC) P0300 will set. The VCM also monitors the CKP sensor signal circuit for malfunctions. The VCM monitors CKP signal and the High and Low resolution signals. The VCM calculates these signals to determine a ratio. When the VCM detects that the ratio is out of normal operating range, the VCM will set a Diagnostic Trouble Code (DTC) P0337 or a DTC P0338.

Now you are still getting a good strong spark. Yes? When pull a plug wire and insert something into the end of it and have someone try to start the car and have the metal object really close to a piece of metal on the engine you are getting a good strong popping blue spark. Yes?

I located another TSB recall that ran out in 2007 but, it is on the fuel injectors sticking. I have attached for your review.

Campaign - Fuel Injector Sticking Closed
Notes
File In Section: 06-Engine Emissions
Bulletin No: 99066F
Date: March, 2003
SPECIAL POLICY
SUBJECT:
99066F - SPECIAL POLICY ADJUSTMENT - SEQUENTIAL CENTRAL PORT
FUEL INJECTION (SCPI) FAILURES IN CALIFORNIA ONLY (YF5
EMISSION EQUIPPED)
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 add the 2002 and 2003 model years to the SCPI Special Policy on certain S/T, M/L, C/K, G, P and W4/NPR truck models. Please discard Special Policy Bulletin Number 99066E, dated February, 2003.
CONDITION
Some customers of 1996, 1997, 1998, 1999, 2000, 2001, 2002 model year S/T, M/L, C/K, G, P, 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 Fuel 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.
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, 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 (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 emissions (RPO YF5). This Special Policy covers all vehicles within these model years, with these engine and emissions RPO's.

Have you had your injectors cleaned?

Okay, last - Looks like you may have some recalls on your vehicle. The dealer may fix these for free. Please contact the dealer service department, give them the VIN number of your car and have them check on these to see if they apply to you.

Please answer the info above and lets take if from there.

Emission Recall

97024 08/01/1997 Recall - Incorrect Exhaust Gas Recirculation Valve Used

General Recalls
99066F 03/01/2003 Campaign - Fuel Injector Sticking Closed
02054 02/01/2003 Campaign - Winshield Wiper Motor Failure
97006 02/01/1997 Campaign - Clutch Pedal Separation From Pivot Bracket

Safety Recalls

NHTSA00V122000 04/27/2000 Recall 00V122000: Restraint System Inadequate
98044 08/01/1998 Recall - Fuel Tank May Contact Body Sill
NHTSA97V096000 06/05/1997 Recall 97V096000: Outboard Seat Belt Replacement
97008A 06/01/1997 Recall - Seat Recliner Hinge Pinch Point Exposed
NHTSA97V066000 04/07/1997 Recall 97V066000: Wheel Inspection/Replacement
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Saturday, November 8th, 2008 AT 6:39 PM
Tiny
RASMATAZ
  • MEMBER
What is the fuel pressure? The fuel pressure specs should be 60-66psi
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Saturday, November 8th, 2008 AT 6:39 PM

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