2000 Suburban 1500 Hard Starting

[WireGuy1950]

Thought I'd run this by you guys to see if there are any better answers than a fuel pump.

My Suburban started running a little rough suddenly. It is also hard to start warm, a lot of cranking and holding the gas pedal down.

I have replaced the plugs and wires (@170,000!), cleaned the MAF sensor and sprayed out the throttle body (did not remove yet).

Today I tested the fuel pressure: Key on 50 PSI falling to <40, started and pressure held @ 52 PSI. after shutting off pressure falls to 40 PSI quickly.

The extended cranking is starting to worry me.

Any thoughts?

[j cAT]

Originally Posted by WireGuy1950

Thought I'd run this by you guys to see if there are any better answers than a fuel pump.

My Suburban started running a little rough suddenly. It is also hard to start warm, a lot of cranking and holding the gas pedal down.

I have replaced the plugs and wires (@170,000!), cleaned the MAF sensor and sprayed out the throttle body (did not remove yet).

Today I tested the fuel pressure: Key on 50 PSI falling to <40, started and pressure held @ 52 PSI. after shutting off pressure falls to 40 PSI quickly.

The extended cranking is starting to worry me.

Any thoughts?

you did a great job troubleshooting this . so why are you asking this question about hard starts poor running ?


fuel pump !

follow the testing proceedure list here at this forum for your vehicle ..this will insure you have all the fuel componets checked ..

If the fuel pump is bad replace the fuel filter,relay also ...make sure the ground wires are not damaged ..

use the delphi pump ...stay away from airtex pumps ..

[Captain Planet]

My 2000 suburban did the same thing 2 years ago. It might be your fuel pressure regulator. It is located on the driver side of the fuel rail. When it fails it lets fuel leak out of the line and it goes into your engine flooding the engine and making warm starts hard. Cold starts are easy because the fuel leaked into the engine has had a chance to evaporate. If your shutting off your truck and the pressure is falling, this may be a sign of a bad regulator. Also, I had a gasoline smell around the engine. I almost forgot, there is a small vacuum line that comes off the regulator, if you pull that off and it is full of gas, the regulator is bad. It is about a $70 part if I recall correctly.

Good luck.

[WireGuy1950]

Just thought I'd update my Hard Starting problem and it's solution, Captain Planet was right.

I did run some more Lucas injector cleaner through it, but that did nothing.

Then I decided to check the fuel pressure regulator.

I disconnected the vacuum line while it was running and it made no difference, so since the part is only $50 I decided that was a good place to start.

After replacing the FPR all the problems went away, the motor starts in half a crank, smooth idle, restarts warm. Problem solved.

I would like to mention a couple of items on replacing the FPR:
1. Although it is a simple job that only takes about 15 minutes, be sure to relieve the fuel pressure before removing the FPR.
2. When you remove the FPR it may come apart, be sure to remove the larger O-ring, the filter screen and the small O-ring which can be hidden in the bore of the fuel rail.
3. Lightly lubricate the O-rings with petroleum jelly before installation.

[j cAT]

Originally Posted by WireGuy1950

Just thought I'd update my Hard Starting problem and it's solution, Captain Planet was right.

I did run some more Lucas injector cleaner through it, but that did nothing.

Then I decided to check the fuel pressure regulator.

I disconnected the vacuum line while it was running and it made no difference, so since the part is only $50 I decided that was a good place to start.

After replacing the FPR all the problems went away, the motor starts in half a crank, smooth idle, restarts warm. Problem solved.

I would like to mention a couple of items on replacing the FPR:
1. Although it is a simple job that only takes about 15 minutes, be sure to relieve the fuel pressure before removing the FPR.
2. When you remove the FPR it may come apart, be sure to remove the larger O-ring, the filter screen and the small O-ring which can be hidden in the bore of the fuel rail.
3. Lightly lubricate the O-rings with petroleum jelly before installation.

the fuel pressure testing proceedure has all these componet tests . you guessed correctly since it did solve your problem ..

what is the fuel pressure now ? should be above 53psi .

good luck ..

[WireGuy1950]

Yes, the fuel pressure is much better now.

Key on (engine off): 53#
Engine on: 48# constant
Key off (engine off): 43# holding

Failure mode on FPR seemed to be an internal bypass, no leakage to the vacuum side of the regulator.