So Pumped to Get Into a 1989 SHO

[auto obsessive garage]

Making some progress here guys. Restored all four factory wheels. This is a serious process involving heavy use of a wire wheel (have extra drill batteries at the ready), sand paper (600 and 1000 grit), and gallons of elbow grease. A great way to burn an entire weekend away...but the SHO deserves it.

 

[auto obsessive garage]

FYI the top wheel has already been cleaned, just not restored. The difference is amazing once the old clear coat is removed and all scratches are sanded out.

 

[blk\blk90]

That looks pretty good. Weaves are a bitch to restore. I need to do that on a set of white slicers and white 18s so I got it kinda easy.

 

[auto obsessive garage]

I've been chugging away on the SHO. I got her a fresh respray while removing all of the nasty surface rust spots that really took away from the great condition of the car. On the way back from a car show this weekend the car began to sputter and finally stalled (on the highway).

Felt just like fuel starvation, but I know I have 3/4 of a tank of gas. I planned to do the fuel filter, but in my experience that's hardly the cause of this. The car will start but then sputters and stalls out. I'm 90% sure it's the fuel pump, which I was super pumped to find out is a tank dropping procedure on this car. That being said, I've seen the cut out the floor method (which I'm game for if you guys support that path).

Such a bummer to add more items to the to do list. Once I get that sorted (hopefully it's just the pump...I'm going to do TB and water pump and everything else while I'm in there (VC gaskets, intake manifold gaskets, plugs, wires, etc.).

Anyone got any personal experience to offer when swapping out the pump? I noticed the write-up didn't have photos. Anyone have a link to one with photos? I'm a visual learner.

 

[luigisho]

If you want to keep it pristine drop the tank. I did it to one car and am reluctant to do it again.

It-- being cutting the access door in the floor

 

[zoomlater]

You can check the pressure at the Schrader valve on the right side of the intake to verify its a fuel pressure issue before dropping the tank. Do you have a pressure gauge to measure it when the pump first turns on, but car not started. If not, you could just depress it to see if the fuel shoots up or not.

 

[NoSlo]

Don't be so sure of the fuel pump based on your gut feeling. The fuel pump doesn't work any harder on the freeway than it does idling in your driveway for an hour. Fuel pressure would normally set a lean code.

Pull the engine codes and you are more likely to get a 211.

 

[auto obsessive garage]

I’ve been doing this long enough to know not to just throw parts at a problem. I will try to pull any codes first and then get the pressure at the rail. If it’s low and the pump is a goner, I will be dropping the tank. Sounds like a blast.


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[zoomlater]

I saw some of the videos from your YouTube channel and they look great. Its nice that your are documenting your journey to give others a more modern step by step procedure on how to fix things. The Sho Phoenix project had a lot of good information, but a video is easier to follow.

 

[auto obsessive garage]

I saw some of the videos from your YouTube channel and they look great. Its nice that your are documenting your journey to give others a more modern step by step procedure on how to fix things. The Sho Phoenix project had a lot of good information, but a video is easier to follow.

Thanks a ton man! Once I get the this stalling issue sorted I can't wait to really tear into the car.

 

[shorage]

my dream sho....

 

[auto obsessive garage]

Finally got back to the SHO and tested the fuel pressure. Once it got up to operating temp it stayed at only 28psi. All the material I found said it should be holding at around 39psi. The pump is making a faint whining sound also.

What do you guys think? I reckon it’s time to swap that pump out.

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[zoomlater]

From what I found on the forum (in the past), is when the engine is at idle, its in the low 30s. WOT is around 40 psi.

 

[auto obsessive garage]

Hmmm if that’s the case it’s not reading too low then. Maybe I will take the car out and simulate the stop and go traffic to see if I can get it to stall out (close to home).

28 just seemed really low as most cars I work on are right around 40psi.


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[NoSlo]

Hmmm if that’s the case it’s not reading too low then. Maybe I will take the car out and simulate the stop and go traffic to see if I can get it to stall out (close to home).

28 just seemed really low as most cars I work on are right around 40psi.

It is not driving the car around that affect it, it is the intake manifold vacuum input to the pressure regulator on the rail. This ensures a constant pressure drop between injection fuel pressure and intake vacuum. Idle has the lowest fuel pressure, because it has the most "vacuum sucking" to assist injector flow, with the regulator returning more fuel to the tank.

Unplug or clamp the vacuum line to the regulator, and you should see pressure climb to the top end of the spec.

 

[auto obsessive garage]

You’re spot on with all that.

I want to drive around in stop and go traffic to see if the fuel pump is overheating. I had an old ****** with a failing pump that would be fine in normal driving, but would sputter and completely stop working if caught in stop and go traffic or really hilly terrain. Car would run fine when given time to completely cool. Swapped out the pump and the issue went away.

I want to simulate that condition again to further test the pump.


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[auto obsessive garage]

[Thread was moved to https://shoforum.com/index.php?threads/fuel-pressure-test-results.139957/ ]

Just in case anyone arrived to this post regarding fuel pump issues.