LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

Fuel System

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Old Jul 15, 2010 | 08:50 AM
  #16  
Chaos1187's Avatar
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Originally Posted by 97SS0594
ive cracked over 600rwhp on stock lines... your stock pump will go along way...

gears
exhaust (including long tube headers)
converter (if your an auto)
free mods (use the search option for these)
throw some nitrous at it and go 12's... you are welcome.
Haha very along the lines I was looking but koolaid is right I need to slow down Im looking for a fast car with some pretty sexy handling I guess is my shot. On what you said I had a question as to the headers cuz there all so different, I was wondering how does that work to match up with the rest of the exhaust? More then likely this is gonna be the next deal (exhaust) I wanted to check the catalytic converters for possible clogs, and have the O2's checked and replaced as well.

Originally Posted by koolaid_kid
Before you begin considering changing any other parts, you need to fix the pressure first. It may take more effort or parts than you think. For example, are you sure it is the pump? Are you sure it is not the FPR? What makes you think this? If you change the pump, what are you going to put in? A stock replacement? A Walbro? A Racetronix with a wiring harness? Which decision did you make, and why?
Once the pressure is steady, it cranks easily, and you are happy, then ask the next question. One step at a time.
As far as the pump replacement I would look online and ask you all what would be recommended as I did in my last post And no I am not sure it is the pump to be honest, If i need to replace the Fuel Pressure Regulator as well that is no problem. As I said before its a 15 year old car that needs some TLC, Im enjoying watchin it come to life one step at a time. What is a nice fuel pump of recommendation? and the benefit of switching to one with its own harness?
Old Jul 15, 2010 | 08:56 AM
  #17  
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Originally Posted by RamAir95TA
There is no benefit to switching to an aftermarket MAF, nor is it needed. Some of the aftermarket MAFs actually are a pain in the *** to tune. Just stick with the stock one.
See and I didnt even know that, the JET one i saw claims 41% more air flow which I thought = good, As well as being compatible with stock and aftermarket parts. Also says it is capable of producing more horsepower and better gas mileage...so i figure since it deals specifically with the a/f ratios it would in fact make a difference?

Car audio is my thing guys I apologize, I appreciate everyones patience greatly...
Old Jul 15, 2010 | 02:59 PM
  #18  
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Originally Posted by Chaos1187
Car audio is my thing
SOUNDS great! Just joshing.

Originally Posted by Chaos1187
See and I didnt even know that, the JET one i saw claims 41% more air flow which I thought = good, As well as being compatible with stock and aftermarket parts. Also says it is capable of producing more horsepower and better gas mileage...so i figure since it deals specifically with the a/f ratios it would in fact make a difference?
AFA airflow, until you are making huge power, the stock MAF flows enough air. The issue is matching the output of the MAF to the input of the ECM. All MAFs are not created equal. Nor are marketing quotes to be believed.
Before moving on to the exhaust, let's address the fuel. Why did you think the pump needed to be replaced? Report your results, please.
If the pump needs to be replaced, the high output (Walbro) are no more expensive than the stock replacements. However, the stock wiring is very weak even for the current draw of a stock pump. If you install a high output pump, you really need to upgrade the wiring harness at the same time. Not to do so is to risk overheating the harness, the pump, or even burning out the pump, as I did with my first Walbro. The Racetronix harness is the best, but the Casper is O.K.
AFA the FPR, if it is the culprit, you can install a stock replacement. Be warned, however, that as a mass produced item, it only estimates the correct pressure. It will be plus or minus a couple of PSI. If you want exact pressure, you need an adjustable unit. Others will disagree, and that is fine. But I have run both, and several brands, and that is my experience.
Old Jul 15, 2010 | 03:32 PM
  #19  
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Originally Posted by koolaid_kid
SOUNDS great! Just joshing.

AFA airflow, until you are making huge power, the stock MAF flows enough air. The issue is matching the output of the MAF to the input of the ECM. All MAFs are not created equal. Nor are marketing quotes to be believed.
Before moving on to the exhaust, let's address the fuel. Why did you think the pump needed to be replaced? Report your results, please.
If the pump needs to be replaced, the high output (Walbro) are no more expensive than the stock replacements. However, the stock wiring is very weak even for the current draw of a stock pump. If you install a high output pump, you really need to upgrade the wiring harness at the same time. Not to do so is to risk overheating the harness, the pump, or even burning out the pump, as I did with my first Walbro. The Racetronix harness is the best, but the Casper is O.K.
AFA the FPR, if it is the culprit, you can install a stock replacement. Be warned, however, that as a mass produced item, it only estimates the correct pressure. It will be plus or minus a couple of PSI. If you want exact pressure, you need an adjustable unit. Others will disagree, and that is fine. But I have run both, and several brands, and that is my experience.
I appreciate the response and the detail. Well I was having to prime the pump turning the ignition to the on position quiet a few times and reading around here it showed to be the culprit (fuel pump). On startup it failed to hold pressure, it would drop but on the times when Id do the key thing a few times and then check it would hold 99% of the time and start and idle. On WOT the pressure would drop a lot and once backed off on the gas would respond better.

Im in the process of buying a few tools that will give me more accurate information on all this aldl cable, obd1 scanner. But Im 90% that it is the pump, and if not its fine Id like to start working somewhere already. Be it the FPR, Fuel Pump, or whatever. As soon as I have some more solid information Ill be sure to post, dont have as much free time as Id like lately.
Old Jul 15, 2010 | 10:13 PM
  #20  
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Getting a scanner is an excellent idea, I use mine all the time. BLMs, timing, knock retard, etc. are all valuable for analysis and improvement.
Fuel pressure, unfortunately, is not a computer parameter on our cars. I have seen newer cars which do, but not us. You need to do it the old fashioned way.
When you start monitoring the actual pressure, you need to record and report actual values. Such as:
Key on, engine off, 42 psi, dropped off to 0 psi in 10 seconds.
Key on, engine off, 42 psi, started engine, dropped to 28 psi with engine running at 1200 rpm.
These sort of measurements will allow us to offer more accurate recommendations.
I am a big fan of upgrading where it needs it. I am against replacing parts just because.
Best of luck, and keep a steady course.
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