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SES always on - no codes other then 12

dyeager535 said:
Opinion: running a fuel pressure gauge all the time is pointless and unnecessary. .
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no offense Dorian, but that is FAR from true... it's crucial for diagnostics on EFI systems... moreso, MPI's, but still valuable with TBI..

it's one of the first things we'll do in the boats, drop a gauge on it and take it for a run... same applies with a vehicle, as Eagle mentioned, it's a great check for WOT... and you certainly can't do that no load under a hood...

not to mention, you'll immediately know you have a fuel issue, I had the pump relay sh*t the bed on Saturday, and knew what it was the minute I turned the key on, without even cranking the rig over... :haha:
 
Royken, I think we clicked save at the same time... Please take another look at the post just before your last one.

Can you give me more info about what fuel pump to upgrade to. When I look at them they say High pressure, but do not give spec's for PSI.
 
THEMCGUIRE said:
1'st off, what do you mean by "but you aren't going to be able to test it running,"

Please don't be annoyed but I went to replace the O2 sensor, could not get it off, but, I found the wire was pinched between two parts of the bell housing. The CES light has been on for as long as I can remember but I had just ignored it before this.

I guess it was like that since the engine was replaced. Over time with vibration I guess it worked the insulation off until it shorted. So I cut the wire, spliced it back together by passing the pinch, disconnected the battery for 30 seconds, took it for a ride and no code.

But, the acceleration could be smoother. Got the fuel pressure kit from autozone and a TBI rebuild kit. Tomorrow I will pull the TBI, rebuild it, and install the adapter and test the fuel pressure.

Thanks for all your help and advise so far.


I have been looking at the Walbro GSS 342 255 that Royken mentioned.

Got the following info"

Walbro "255" LPH GSS-317 12.5V 43psi 7.5amps 229.02 Ltr/Hr
Walbro "255" LPH GSS-317 12.5V 58psi 9.0amps 201.89 Ltr/Hr
Walbro "255" LPH GSS-317 12.5V 73psi 10.5amps 147.00 Ltr/Hr

Walbro "255" LPH GSS-317 14.0V 43psi 8.0amps 261.83 Ltr/Hr
Walbro "255" LPH GSS-317 14.0V 58psi 10amps 230.92 Ltr/Hr
Walbro "255" LPH GSS-317 14.0V 73psi 11.5amps 182.97 Ltr/Hr

Walbro "255 High Pressure" LPH GSS-342 12.5V 43psi 7amps 233.4 Ltr/Hr
Walbro "255 High Pressure" LPH GSS-342 12.5V 58psi 9amps 210.10 Ltr/Hr
Walbro "255 High Pressure" LPH GSS-342 12.5V 73psi 10.5amps 189.3 Ltr/Hr

Walbro "255 High Pressure" LPH GSS-342 14.0V 43psi 8amps 264.4 Ltr/Hr
Walbro "255 High Pressure" LPH GSS-342 14.0V 58psi 9.5amps 242.9 Ltr/Hr
Walbro "255 High Pressure" LPH GSS-342 14.0V 73psi 11amps 220.8 Ltr/Hr

All tests show fuel pressure of 43, 58 and 73 psi.

Won't this blow out my pressure regulator ?

My max pressure should be 14 psi, correct ? Am I looking at the wrong pump ?


Oh btw, I put a 1993 Cherokee steering shaft in today as well. OMG 30 min work and the steering is beautiful now. FYI....
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the pump is a replacement for an 89 z28... trying to dig up the part #....

it's not a high pressure pump, it's rated for like 45 lb's... and no, you wont blow out a regulator.. it has nothing to do with that... as long as you have a clean return line with solid hose connections, it's fine.. all it does is "polish" the fuel by circulating it thru the tank/filter more.... :haha:

and yes, you could run it with the stock regulator..
 
dyeager535 said:
Opinion: running a fuel pressure gauge all the time is pointless and unnecessary.
Click to expand...
Ahhh yes and no?

As mentioned above it's another gauge so you always know.

But the key point for me when tuning is you can have perfect fuel pressure set to say 15 PSI. Blip throttle and rev up etc... and still perfect 15 PSI. Floor it on road and see fuel pressure dropping as load increases or RPM increases!

This can only be found if you can see the gauge while driving WOT high RPM. The pump is good, the pressure is good. But the pump can not keep up with enough flow and pressure during the high demands.

I made up a temp so I could use it on other peoples rigs! Here's some pics. BTW if I had to do it again, which I am... I will use the CFM adapter and not the one from Actron, it was more work but occasionally drips!

100_1259.JPG

100_1260.JPG
 
my boss has that same Actron one we use on the boats, it work's, but your right, I like the CFM one a bit better that is on Mutt...
 
ryoken said:
my boss has that same Actron one we use on the boats, it work's, but your right, I like the CFM one a bit better that is on Mutt...
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What hose is that? I have the CFM adapter, and would love to put a hose on mine, clamp under hood when all is good, and clamp to wiper when i need to check WOT.

Afraid mine is running lean at WOT.

Hijack off.
 
well, Eagle can answer that since it's his, our work one is a bit different hose setup..

the one for my autometer setup is similar, and is just a 6 AN braided hose.. hang on, i'll find it...
 
right.. that AM setup just has the 1/8 npt to AN adapter fitting, but any set up to 1/8 will work...
 
Sorry, I meant with the autozone setup you can't test it while *driving*. It's got a fitting on both ends, it's not just a hose you can easily extend so that you could. That was disappointing.

Someone would have to answer the question as to how much pressure a split hose situation will show. I'd expect near nothing.
 
dyeager535 said:
Someone would have to answer the question as to how much pressure a split hose situation will show. I'd expect near nothing.
Click to expand...

Depends on the split? :haha:

Really any leak on hose in tank, that close to pump is a dramatic loss of pressure.

I seem to remember 6 PSI from a split hose in tank that had a good pump.
 
ryoken said:
no offense Dorian, but that is FAR from true... it's crucial for diagnostics on EFI systems... moreso, MPI's, but still valuable with TBI..

it's one of the first things we'll do in the boats, drop a gauge on it and take it for a run... same applies with a vehicle, as Eagle mentioned, it's a great check for WOT... and you certainly can't do that no load under a hood...

not to mention, you'll immediately know you have a fuel issue, I had the pump relay sh*t the bed on Saturday, and knew what it was the minute I turned the key on, without even cranking the rig over... :haha:
Click to expand...

No offense, that's why I said it was opinion, and I can't get mad if someone disagrees with opinion, not fact.

My thinking is, once you set fuel pressure (or test it), the only time it will change after is if something goes wrong...and if you don't notice the way it runs being worse, what are the chances there is a problem that you'd see with a gauge? Yes, it can happen. I'm playing law of averages here.

Along those same lines, you could run a gauge showing O2 output, TPS voltage, intake vacuum, MAP voltage, etc. just in case one of those failed. None of those runs the risk of creating a fuel leak though. We normally expect the SES to tell us something is going on. Not always the case of course, but nonetheless we trust the system for those sensors, why would we distrust it on telling us of a fueling problem?

Anyway, that's how I formed my opinion. Don't get me wrong, I think they are a VERY useful and necessary diagnostic tool. Luckily autozone loans them free. :)
 
I agree with your opinion. It's why I made the temp gauge to use and verify when tuning.

After that it's a long shot something will change. And if your loosing pressure then it will show and go back to diagnosing and checking fuel pressure.
 
It would have been nice if GM had been generous and just set TBI up with a schrader valve inline somewhere up top.

Oddly, even the 197x EFI Cadillac/Olds rail setup has the schrader valve in it, like most of the 80's/90's non-TBI injection stuff apparently does.

Maybe GM just figured they had such a broad range of "acceptable" pressure in TBI that it was either a pump works or it doesn't situation? Anyway, off-topic. I dislike testing pressure on TBI because I hate the gas bath. I suppose if you cracked the line at the filter and then used the fitting on the flexible portion of the line for the pressure gauge, it would leak out before it reached where you are trying to work. :)

You'll normally hear people talk about connecting the pressure tester fitting at the TB or at the fuel filter. Both of those locations, if clamped properly (IE factory routing of the lines) are very hard to deal with. Thus, tap into where the flexible line meets the frame rail hard line.
 
I have ordered the pressure adjustor from CFM and an ACDelco pump as suggested.

I dislike removing the fuel line from the TB. It is in such an bad location but it has to be done. I always worry about cross threading when reinstalling it. I did that back in 1974 when changing the fuel filter on my 1973 Cutlass supreme and started a fire.

If the gauge adapter is installed does it have to be removed or just leave it there ?

If you can leave it there, Can you install the gauge directly into the adapter so that you can check the pressure anytime by just opening the hood ?
 
THEMCGUIRE said:
I have ordered the pressure adjustor from CFM and an ACDelco pump as suggested.

I dislike removing the fuel line from the TB. It is in such an bad location but it has to be done. I always worry about cross threading when reinstalling it. I did that back in 1974 when changing the fuel filter on my 1973 Cutlass supreme and started a fire.

If the gauge adapter is installed does it have to be removed or just leave it there ?

If you can leave it there, Can you install the gauge directly into the adapter so that you can check the pressure anytime by just opening the hood ?
Click to expand...


Yes, you can leave the adapter and gauge.

Yes, you should be concerned about cross threading it. I did, twice. The adapters that get fubar'd are dealer only, and the hard/soft line is hard to come by.

Unbolt the couple of fuel line hold downs (1 is back of the block, dont' remember if there is another) before trying to move these lines. You essentially have to push the feed line back an inch, so having it loose makes it easier.

Get it threaded in to the TBI, then bend as needed to clear obstructions and get it back in the factory clamp.

Good luck!
 
Thanks. The PO put in a Jasper rebuilt engine... He did not complete every stock connection. The fuel line on this is guided to the TBI but not locked down except on the frame so it is easy to move.

Put new belts on today and found that the rear bracket for the power steering pump was not attached. Just floating there on one bolt.

That was a painful surprise, I dislike working on my back at my age. Took almost 2 hours to get everything out of the way to get that bracket back in.

Since I did not know about the missing bracket for the fuel line, how critical is that for safety. Or can I just leave it like it is. Had the truck for over 10 years now and it has never been an issue.
 
eagle mark said:
Depends on the split? :haha:

Really any leak on hose in tank, that close to pump is a dramatic loss of pressure.

I seem to remember 6 PSI from a split hose in tank that had a good pump.
Click to expand...

With TPI pump, I had the in-tank hose split and the gauge read about 2-3psi without the engine running.
 
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