Eaton SG 1989 w/low fuel pressure
11-12-2006, 04:47 PM
#1
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Eaton SG 1989 w/low fuel pressure
I have had the car now for about 4 months and I have put about 2000 miles on it with no issues. I upgraded from a 6.5 lb pulley to a 8 psi pulley and the problems started. The car would drive fine but would have fuel starvation from time to time when cruising at 60 mph. The fuel starvation got worse and one day I barely made it home. I replaced the worn out caps/rotors/fuel filter and I thought that fixed the problem until I took the shark on a 50 miles trip.
In the meantime I got a copy of Cameron's GT eaton 6.7 PSI sharktuned chip. While waiting on the chip I tested the in-tank fuel pump and that was dead so I installed a new intank pump. The Cyberdyne fuel pressure guage reads 24 psi at idle. At normal driving its steady at 30 psi (in 5th at 60mph). The pressure with the bad in-tank fuel pump would go as high at 36 psi in any gear. With the new in-tank pump it will go to 40 psi at 6000 rpm. With the fuel pump relay bypassed it will increase to 30 psi and same when I remove the vacuum hose off the dampener.
Is these reading too low even if I am running #30 injectors? I do not have access to a ST so please don't recommend this
. I do have a new Begi that I am considering installing to increase the fuel pressure. What can I do to test the fuel delivery system? Should I remove the vacuum off the fuel regulator and see if I increases the pressure?
Help, this SG is driving me crazy and my wife is threatening me, lol. Btw, I was hoping to get help by subscribing to the magazine "Whipped" but I learned its not a real magazine
In the meantime I got a copy of Cameron's GT eaton 6.7 PSI sharktuned chip. While waiting on the chip I tested the in-tank fuel pump and that was dead so I installed a new intank pump. The Cyberdyne fuel pressure guage reads 24 psi at idle. At normal driving its steady at 30 psi (in 5th at 60mph). The pressure with the bad in-tank fuel pump would go as high at 36 psi in any gear. With the new in-tank pump it will go to 40 psi at 6000 rpm. With the fuel pump relay bypassed it will increase to 30 psi and same when I remove the vacuum hose off the dampener.
Is these reading too low even if I am running #30 injectors? I do not have access to a ST so please don't recommend this
. I do have a new Begi that I am considering installing to increase the fuel pressure. What can I do to test the fuel delivery system? Should I remove the vacuum off the fuel regulator and see if I increases the pressure?Help, this SG is driving me crazy and my wife is threatening me, lol. Btw, I was hoping to get help by subscribing to the magazine "Whipped" but I learned its not a real magazine
11-12-2006, 05:13 PM
#2
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Hi Gio-
That fuel pressure souds WAY low. I've got the 30# injectors, and am running about 48psi on the fuel. I do have an adjustable fuel pressure regulator, but 48psi is about what the stock fuel should be. Hmmm.. I need to think about it....
That fuel pressure souds WAY low. I've got the 30# injectors, and am running about 48psi on the fuel. I do have an adjustable fuel pressure regulator, but 48psi is about what the stock fuel should be. Hmmm.. I need to think about it....
11-12-2006, 05:13 PM
#3
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Have you checked to see what the actual air fuel ratio is?
The older cars had 24# injectors with lower pressure regulators.
The newer cars had 19# injectors with high pressure regulators.
You have a newer car. If you use 30# injectors with the stock higher-pressure regulators, then you're probably running way too rich. ESPECIALLY if you're using the BEGI.
On a "newer" car i work on, i have lower pressure regulators and 30# injectors. If I add in any fuel via the BEGI, it runs too rich and hesitates at higher RPMs.
And its hard to say what the chip is doing...
What are you air/fuel ratios? You really gotta goto a dyno and get them to check it.
The older cars had 24# injectors with lower pressure regulators.
The newer cars had 19# injectors with high pressure regulators.
You have a newer car. If you use 30# injectors with the stock higher-pressure regulators, then you're probably running way too rich. ESPECIALLY if you're using the BEGI.
On a "newer" car i work on, i have lower pressure regulators and 30# injectors. If I add in any fuel via the BEGI, it runs too rich and hesitates at higher RPMs.
And its hard to say what the chip is doing...
What are you air/fuel ratios? You really gotta goto a dyno and get them to check it.
11-12-2006, 05:33 PM
#4
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Btw, mine has the 85-86 fuel pressure regulator if that counts for anything. Should I go back to the stock 89 FPR? I did a dyno a few months ago and the car was way too lean but that was before the Sharktuned copy of Cameron's GT. The ARM1 gauge shows the car is not running lean but that was also the case when I was running with the stock chip.
11-12-2006, 08:53 PM
#5
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You are pissing into the wind if you goof around without the benefit of a wide-band A/F gauge. Run too lean under boost and you're going to be looking for an engine real fast. An onboard WB A/F guage isn't all that expensive!
That said, Andy's suggestion for '87-onward cars running his system was to use the '85-'86 FPR along with 30# injectors, and to tune from there with the BEGI.
Obvioulsy, that was the best thing available when Andy was developing his system and we didn't hear of anyone grenading a boosted engine. Now, the Shark Tuner is the best answer.
That said, Andy's suggestion for '87-onward cars running his system was to use the '85-'86 FPR along with 30# injectors, and to tune from there with the BEGI.
Obvioulsy, that was the best thing available when Andy was developing his system and we didn't hear of anyone grenading a boosted engine. Now, the Shark Tuner is the best answer.
11-12-2006, 09:04 PM
#6
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Brian, so technically I should not be having fuel starvation and low pressure problems since I have a shark tuned chip installed (not optimized for my car though). How can I go by checking the fuel system? Should I go back to the normal chip and install the begi until I can get my hands on a ST?
11-12-2006, 09:15 PM
#7
Three Wheelin'
If you have a roots blower running about 7 psi (maybe even 8) boost, 30# injectors, an 85-86 fpr and stock exhaust (I think that you said you have an RMB - so do I) you should take some AFR readings on the car. You are probably good because the only difference in the cars really is the cams. Mine is a GT.
Either buy the Innovate LM-1 or LC-1 with wideband O2 sensor and log your AFR, or take it to a shop with a dyno where they can give you AFR readings. Purchasing an RRFPR will be a waste of money without the ability to know your AFR readings anyway. You won't have anything to tune against.
Good luck
Either buy the Innovate LM-1 or LC-1 with wideband O2 sensor and log your AFR, or take it to a shop with a dyno where they can give you AFR readings. Purchasing an RRFPR will be a waste of money without the ability to know your AFR readings anyway. You won't have anything to tune against.
Good luck
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11-12-2006, 10:25 PM
#8
ok so no brainer on this question then, if you have a 87 shark and are boosting it to 7 psi ( i assume the that one has at least a fuel rail gauge installed) what is your feul presure reading at idel then? all you have to do is match that and start from there. Andrew what is your ideling fuel presure and what ratio fmu are you running if you are using on?
11-12-2006, 10:47 PM
#9
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Originally Posted by Andrew Olson
Hi Gio-
That fuel pressure souds WAY low. I've got the 30# injectors, and am running about 48psi on the fuel. I do have an adjustable fuel pressure regulator, but 48psi is about what the stock fuel should be. Hmmm.. I need to think about it....
That fuel pressure souds WAY low. I've got the 30# injectors, and am running about 48psi on the fuel. I do have an adjustable fuel pressure regulator, but 48psi is about what the stock fuel should be. Hmmm.. I need to think about it....
11-12-2006, 11:24 PM
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Although I have a Shark Tuner, it took adjusting my fuel pressure reg up to 40 psi at idle (with vacuum) do get the shark tuner into the range that it could adjust the upper left A/F cells. (about 48 psi without vacuum)
The weather is preventing me from getting at much more than about 6 cells. It's hard to pull boost in the garage!
The weather is preventing me from getting at much more than about 6 cells. It's hard to pull boost in the garage!
11-12-2006, 11:39 PM
#11
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Im in the low 40s at idle(as low as i could get it) and 75-80ish under boost.
30lbs injectors and I head toward lean at the higher rpms. Now that i have a new pump i may take the pressure up a tad more.
A Shark tune is in the future...safest way to do it. Im debating to go up to 39lbs injectors also.
For the price the LM-1 is the way to go
press record..foot to the floor...look at it later!
the rpm scale is NOTcorrect on the bottom one.
30lbs injectors and I head toward lean at the higher rpms. Now that i have a new pump i may take the pressure up a tad more.
A Shark tune is in the future...safest way to do it. Im debating to go up to 39lbs injectors also.
For the price the LM-1 is the way to go
press record..foot to the floor...look at it later!
the rpm scale is NOTcorrect on the bottom one.
11-13-2006, 12:41 AM
#12
Three Wheelin'
I am familiar with the car and the kit.
If I recall correctly, Andy designed the Stage I Eatons to run with 30# injectors (without a rising rate FPR) and at the lower fuel pressure of the 85/86 (to deal with richness at idle). This was designed for a low level of boost that would also not require higher fueling at high RPMs.
By changing to the higher PSI pulley, you may have interfered with the original game plan.
So you should probably install the BEGI and spend some time on a tuning session with a WB o2 sensor.
I don't seem to have any starvation issues running 30# injectors and 60 psi fuel under boost (or less)--I lean more to the rich side.
I suspect if I had a freer flowing exhaust with some scavenging this might change a bit.
Bottom line, if you're going to fiddle around with this, I think you're much better off taking a more comprehensive, thoughtful and customized approach (instead of just plugging and playing and mixing and matching) before you screw something up. The expense of doing it right and understanding and fixing the problem will be an awful lot less expensive than damaging something.
If I recall correctly, Andy designed the Stage I Eatons to run with 30# injectors (without a rising rate FPR) and at the lower fuel pressure of the 85/86 (to deal with richness at idle). This was designed for a low level of boost that would also not require higher fueling at high RPMs.
By changing to the higher PSI pulley, you may have interfered with the original game plan.
So you should probably install the BEGI and spend some time on a tuning session with a WB o2 sensor.
I don't seem to have any starvation issues running 30# injectors and 60 psi fuel under boost (or less)--I lean more to the rich side.
I suspect if I had a freer flowing exhaust with some scavenging this might change a bit.
Bottom line, if you're going to fiddle around with this, I think you're much better off taking a more comprehensive, thoughtful and customized approach (instead of just plugging and playing and mixing and matching) before you screw something up. The expense of doing it right and understanding and fixing the problem will be an awful lot less expensive than damaging something.
11-13-2006, 01:23 AM
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Originally Posted by Tony
For the price the LM-1 is the way to go
press record..foot to the floor...look at it later!
11-13-2006, 03:29 AM
#14
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Gio:
Just what are the symptoms you are having? "Fuel starvation" while cruising at 60 and "barely making it home" don't sound like fuel starvation.
Just what are the symptoms you are having? "Fuel starvation" while cruising at 60 and "barely making it home" don't sound like fuel starvation.
11-13-2006, 09:44 AM
#15
Three Wheelin'
Let me try to be clear. Giovanni has a copy of the SharkTuned chip that I made for my car and that Sab and I are running with great success. The AFR readings were previously posted here on the board. Baselining the setups, here is what we have.
Blower: Cameron - Roots type Giovanni - Roots type
Boost: Cameron - 6.7 psi Giovanni - 8 psi
FRP: Cameron - 85/86 FPR Giovanni - 85/86 FPR
Injectors: Cameron - 30# Giovanni - 30#
Exhaust: Cameron - Stock GT / RMB Giovanni - Stock S4 / RMB
Cams: Cameron - GT Giovanni - S4
The only differences are that Giovanni is running about 1 psi more boost and I have a GT, hence I have GT cams and GT exhaust.
I repeat my recommendation. Do nothing until you get some AFR readings on your current set up. You might be just fine.
If you want to tweak for the sake of tweaking, get the SharkTuner. It is the best way to go IMHO. But you will need a wideband O2 sensor for that.
Giovanni,
I think that you might also confuse people by describing various problems that you have had at different times. For example, you believe you were going lean BEFORE you had the SharkTuned chip in your car and BEFORE you found that you had a bad in tank fuel pump and had it replaced. Now that you have the SharkTuned chip from my car and have replaced the bad fuel pump, do you still think that you are going lean? I think that if you get some reliable AFR readings, you may be pleasantly surprised.
Blower: Cameron - Roots type Giovanni - Roots type
Boost: Cameron - 6.7 psi Giovanni - 8 psi
FRP: Cameron - 85/86 FPR Giovanni - 85/86 FPR
Injectors: Cameron - 30# Giovanni - 30#
Exhaust: Cameron - Stock GT / RMB Giovanni - Stock S4 / RMB
Cams: Cameron - GT Giovanni - S4
The only differences are that Giovanni is running about 1 psi more boost and I have a GT, hence I have GT cams and GT exhaust.
I repeat my recommendation. Do nothing until you get some AFR readings on your current set up. You might be just fine.
If you want to tweak for the sake of tweaking, get the SharkTuner. It is the best way to go IMHO. But you will need a wideband O2 sensor for that.
Giovanni,
I think that you might also confuse people by describing various problems that you have had at different times. For example, you believe you were going lean BEFORE you had the SharkTuned chip in your car and BEFORE you found that you had a bad in tank fuel pump and had it replaced. Now that you have the SharkTuned chip from my car and have replaced the bad fuel pump, do you still think that you are going lean? I think that if you get some reliable AFR readings, you may be pleasantly surprised.