Sick of it
08-01-2010, 07:44 PM
#1
Team Owner
Thread Starter
Member Since: Jan 2009
Location: Somewhere in Mo
Posts: 73,434
Likes: 0
Received 31 Likes
on
27 Posts
St. Jude Donor '09-'10, '14
Sick of it
This past year I replaced every part of the fuel system. I had a bad FPR but I decided to replace everything just cause and so I would know the history of the system. Especially since fuel delivery issues are so common.
Well right after I got back from the Power Tour I started noticing a cold hard start.
I was hoping it would magically go away and it was my imagination. Well although I do have an overly active imagination at times it didn't go away.
I did a fuel pressure test and I got 42 with a leak down to only about 30 after 30 minutes or so.
Well it continued to bug me so I went today and hooked up the tester and I got zero. Started it up and it only went to aout 35. Pump runs for the 2 to 3 seconds so the relay is good. Just for the heck of it I tested the injectors and they ohmed out at 16, right on the money. I know that doesn't check pressure but I thought I would test them anyway because I get a weird hiccup in closed loop.
I need to look at the FPR line to see if there's any presence of fuel but it's new so I'm temporarily ruling that out. I'll have to wait to pull the fuel pump because I just filled up the other day.
Man, I'm sick of it. You spend all the time and money on something and one of the somethings is bad from the store!
Some of you may recall the fiasco I had with Thunder Racing and my lost Racetronics FP, so I got one at Oreilly.
I'm really thinking it is the pump though.
Well right after I got back from the Power Tour I started noticing a cold hard start.
I was hoping it would magically go away and it was my imagination. Well although I do have an overly active imagination at times it didn't go away.
I did a fuel pressure test and I got 42 with a leak down to only about 30 after 30 minutes or so.
Well it continued to bug me so I went today and hooked up the tester and I got zero. Started it up and it only went to aout 35. Pump runs for the 2 to 3 seconds so the relay is good. Just for the heck of it I tested the injectors and they ohmed out at 16, right on the money. I know that doesn't check pressure but I thought I would test them anyway because I get a weird hiccup in closed loop.
I need to look at the FPR line to see if there's any presence of fuel but it's new so I'm temporarily ruling that out. I'll have to wait to pull the fuel pump because I just filled up the other day.
Man, I'm sick of it. You spend all the time and money on something and one of the somethings is bad from the store!
Some of you may recall the fiasco I had with Thunder Racing and my lost Racetronics FP, so I got one at Oreilly.
I'm really thinking it is the pump though.
08-01-2010, 09:10 PM
#2
Race Director
It's all the "Hot Roddin" you did on Power Tour Mike. 
Sorry, couldn't resist.
Hope you get it worked out. I am not a mechanic, so not much help.
Sorry, couldn't resist.
Hope you get it worked out. I am not a mechanic, so not much help.
08-01-2010, 09:32 PM
#4
Le Mans Master
Member Since: Feb 1999
Location: levittown pa. usa Even a bad day with my `Vette, is better than a good day at work
Posts: 6,470
Likes: 0
Received 2 Likes
on
2 Posts
St. Jude Donor '10
Stuff like that is why its called a "hobby" bro` ( well, that & the "Corvette Tax" on almost every part you buy for these cars )
08-01-2010, 11:12 PM
#6
Race Director
Sarge....tape the gauge to the windshield and drive it. Tell me what it does under load. You did replace the pulsator when you had the pump out and clamped all of the connections, correct?
The fact that you got zero lbs on the 2 second prime points to pump or regulator. Pinch off the return line and try it again in the AM after it has sat overnight. If you get zero still, run 12V to terminal G on the ALDL and see what it does.
The fact that you got zero lbs on the 2 second prime points to pump or regulator. Pinch off the return line and try it again in the AM after it has sat overnight. If you get zero still, run 12V to terminal G on the ALDL and see what it does.
08-02-2010, 01:56 AM
#7
Drifting
Friz makes a good point with the fuel pump pulsator... with age (and ethanol), it can swell and restrict fuel flow. Replace with fuel injection grade hose.
08-02-2010, 08:51 AM
#8
Team Owner
Thread Starter
Member Since: Jan 2009
Location: Somewhere in Mo
Posts: 73,434
Likes: 0
Received 31 Likes
on
27 Posts
St. Jude Donor '09-'10, '14
Sarge....tape the gauge to the windshield and drive it. Tell me what it does under load. You did replace the pulsator when you had the pump out and clamped all of the connections, correct?
The fact that you got zero lbs on the 2 second prime points to pump or regulator. Pinch off the return line and try it again in the AM after it has sat overnight. If you get zero still, run 12V to terminal G on the ALDL and see what it does.
The fact that you got zero lbs on the 2 second prime points to pump or regulator. Pinch off the return line and try it again in the AM after it has sat overnight. If you get zero still, run 12V to terminal G on the ALDL and see what it does.
When I changed the pump I put new everything except for the sending unit, to include new hose for the pulsator action. I could have a clamping issue and that's what I'll check first.
Funny thing, this morning it fired right up.
IIRC I also saved my old pump so I will put it back on and see what happens if I determine it's in the pump.
08-27-2010, 01:54 PM
#10
Team Owner
Thread Starter
Member Since: Jan 2009
Location: Somewhere in Mo
Posts: 73,434
Likes: 0
Received 31 Likes
on
27 Posts
St. Jude Donor '09-'10, '14
Ok it's cooled down and I've had some time to fiddle with this so here's what I found.
Primed pump, only got about 32 lbs. Manual says between 40.5 and 47. Bleed down to about 10 in 30 seconds. Then to zero in about another couple minutes.
put old fuel pump on. Same thing.
Pinched delivery line, still bleed down. Pinched return line still bleed down. It has new Bosch II's but the manual states it's the injectors if these procedures result in what my findings were.
I didn't believe it could be the injectors so I performed all the tests countless times. Taped gauge to windshield, couldn't see the darn thing very well but it appeared the pressure stayed in the low 30 range.
Went back, did all tests again with the same results. i didn't have a way to put 12 volts to the pump so I said the heck with it and pinched the return line and started it up. Pressure went up to 50 so I turned the car off. 20 minutes later still had 50 lbs.
So am I correct in thinking my diaphram went bad that I just replaced in the spring? I've read countless threads that spoke of diaphrams going bad or people purchasing bad ones to begin with.
Also I tried the pinching again but couldn't get it to go up to 50 this time. I'm wondering if it was operator error though on getting the lines pinched off. It seems it's a booger to get them pinched properly. I will also add that when I replaced the pump, diaphram, injectors and filter this spring, I was getting 42 at prime and it only bled down to about 30 after an hour.
Thoughts, comments, smart remarks?
(Mod, you may move this to tech if you wish. I just continued on with this one as it posted in Gen. Thanks)
Primed pump, only got about 32 lbs. Manual says between 40.5 and 47. Bleed down to about 10 in 30 seconds. Then to zero in about another couple minutes.
put old fuel pump on. Same thing.
Pinched delivery line, still bleed down. Pinched return line still bleed down. It has new Bosch II's but the manual states it's the injectors if these procedures result in what my findings were.
I didn't believe it could be the injectors so I performed all the tests countless times. Taped gauge to windshield, couldn't see the darn thing very well but it appeared the pressure stayed in the low 30 range.
Went back, did all tests again with the same results. i didn't have a way to put 12 volts to the pump so I said the heck with it and pinched the return line and started it up. Pressure went up to 50 so I turned the car off. 20 minutes later still had 50 lbs.
So am I correct in thinking my diaphram went bad that I just replaced in the spring? I've read countless threads that spoke of diaphrams going bad or people purchasing bad ones to begin with.
Also I tried the pinching again but couldn't get it to go up to 50 this time. I'm wondering if it was operator error though on getting the lines pinched off. It seems it's a booger to get them pinched properly. I will also add that when I replaced the pump, diaphram, injectors and filter this spring, I was getting 42 at prime and it only bled down to about 30 after an hour.
Thoughts, comments, smart remarks?
(Mod, you may move this to tech if you wish. I just continued on with this one as it posted in Gen. Thanks)
08-27-2010, 02:40 PM
#11
Safety Car
Ok it's cooled down and I've had some time to fiddle with this so here's what I found.
Primed pump, only got about 32 lbs. Manual says between 40.5 and 47. Bleed down to about 10 in 30 seconds. Then to zero in about another couple minutes.
put old fuel pump on. Same thing.
Pinched delivery line, still bleed down. Pinched return line still bleed down. It has new Bosch II's but the manual states it's the injectors if these procedures result in what my findings were.
I didn't believe it could be the injectors so I performed all the tests countless times. Taped gauge to windshield, couldn't see the darn thing very well but it appeared the pressure stayed in the low 30 range.
Went back, did all tests again with the same results. i didn't have a way to put 12 volts to the pump so I said the heck with it and pinched the return line and started it up. Pressure went up to 50 so I turned the car off. 20 minutes later still had 50 lbs.
So am I correct in thinking my diaphram went bad that I just replaced in the spring? I've read countless threads that spoke of diaphrams going bad or people purchasing bad ones to begin with.
Also I tried the pinching again but couldn't get it to go up to 50 this time. I'm wondering if it was operator error though on getting the lines pinched off. It seems it's a booger to get them pinched properly. I will also add that when I replaced the pump, diaphram, injectors and filter this spring, I was getting 42 at prime and it only bled down to about 30 after an hour.
Thoughts, comments, smart remarks?
(Mod, you may move this to tech if you wish. I just continued on with this one as it posted in Gen. Thanks)
Primed pump, only got about 32 lbs. Manual says between 40.5 and 47. Bleed down to about 10 in 30 seconds. Then to zero in about another couple minutes.
put old fuel pump on. Same thing.
Pinched delivery line, still bleed down. Pinched return line still bleed down. It has new Bosch II's but the manual states it's the injectors if these procedures result in what my findings were.
I didn't believe it could be the injectors so I performed all the tests countless times. Taped gauge to windshield, couldn't see the darn thing very well but it appeared the pressure stayed in the low 30 range.
Went back, did all tests again with the same results. i didn't have a way to put 12 volts to the pump so I said the heck with it and pinched the return line and started it up. Pressure went up to 50 so I turned the car off. 20 minutes later still had 50 lbs.
So am I correct in thinking my diaphram went bad that I just replaced in the spring? I've read countless threads that spoke of diaphrams going bad or people purchasing bad ones to begin with.
Also I tried the pinching again but couldn't get it to go up to 50 this time. I'm wondering if it was operator error though on getting the lines pinched off. It seems it's a booger to get them pinched properly. I will also add that when I replaced the pump, diaphram, injectors and filter this spring, I was getting 42 at prime and it only bled down to about 30 after an hour.
Thoughts, comments, smart remarks?
(Mod, you may move this to tech if you wish. I just continued on with this one as it posted in Gen. Thanks)
I just re-read your posts and Im sorta confused, (I will go back through again) when you crimped off the fuel delivery line did the pressure drop?
08-27-2010, 03:55 PM
#12
Team Owner
Thread Starter
Member Since: Jan 2009
Location: Somewhere in Mo
Posts: 73,434
Likes: 0
Received 31 Likes
on
27 Posts
St. Jude Donor '09-'10, '14
Sounds like your fuel pump check valve or the pulsator as mentioned above... I would venture a guess at pulsator because from what I have experienced, when a check valve goes, the pressure drops to 0 right after the fuel pump stops...
I just re-read your posts and Im sorta confused, (I will go back through again) when you crimped off the fuel delivery line did the pressure drop?
I just re-read your posts and Im sorta confused, (I will go back through again) when you crimped off the fuel delivery line did the pressure drop?
The pressure also is only going up to about 32 when I prime the pump.
08-27-2010, 05:22 PM
#14
Safety Car
yes it did drop when I pinched the delivery line. Therewas only one time it didn't drop and that was one of the times I had the return line pinched and started the car. The pressure went up to 50 and stayed when I shut the car off. It's kinda hard pinching these lines and it always went down except for the one time I started it. Which, if I'm reading the manual correctly states it's the FPR.
The pressure also is only going up to about 32 when I prime the pump.
The pressure also is only going up to about 32 when I prime the pump.
If you can get the line pinched real good and it still bleeds off, I would check for leaks in the fuel line (Im sure you would smell it but its always good to check). The only things it can be from there are the injectors or FPR... If it doesnt bleed off then its the fuel pump or the pulsator tube...
Let me know when you figure it out
08-27-2010, 05:58 PM
#15
Race Director
Sarge....if pinching off the return line results in strong pressure that holds, the fuel pressure regulator is the only answer. If you had a leaking check valve, pulsator, or injectors, pinching off the return line would have no effect. The pressure would then bleed off on the supply line.
The FPR is like a dam in a river. If the dam is leaking, pressure falls. Plug the leak, and pressure rises.
The FPR is like a dam in a river. If the dam is leaking, pressure falls. Plug the leak, and pressure rises.
08-28-2010, 05:47 PM
#16
Team Owner
Thread Starter
Member Since: Jan 2009
Location: Somewhere in Mo
Posts: 73,434
Likes: 0
Received 31 Likes
on
27 Posts
St. Jude Donor '09-'10, '14
Well I was sure it was the FPR because of my checks. I changed it today and it still leaks down.
I'm beginning to lean to the injectors I installed from Jon. I pinch the delivery line and it bleeds down, same with the return line. (I couldn't get it to duplicate the results I had starting the car and the pressure holding with the return line pinched.
Now I know it's a booger to get these lines pinched correctly but it would at least slow down.
The thing I'm bumfuzzled about is I get no smoke at start up and it starts right up if I let it sit for few minutes.
Like I say, I'm leaning to injectors. Anyone ever hear of bad injectors from Jon?
I'm beginning to lean to the injectors I installed from Jon. I pinch the delivery line and it bleeds down, same with the return line. (I couldn't get it to duplicate the results I had starting the car and the pressure holding with the return line pinched.
Now I know it's a booger to get these lines pinched correctly but it would at least slow down.
The thing I'm bumfuzzled about is I get no smoke at start up and it starts right up if I let it sit for few minutes.
Like I say, I'm leaning to injectors. Anyone ever hear of bad injectors from Jon?
08-28-2010, 06:12 PM
#17
Drifting
Member Since: Nov 2009
Posts: 1,884
Likes: 0
Received 0 Likes
on
0 Posts
Well I was sure it was the FPR because of my checks. I changed it today and it still leaks down.
I'm beginning to lean to the injectors I installed from Jon. I pinch the delivery line and it bleeds down, same with the return line. (I couldn't get it to duplicate the results I had starting the car and the pressure holding with the return line pinched.
Now I know it's a booger to get these lines pinched correctly but it would at least slow down.
The thing I'm bumfuzzled about is I get no smoke at start up and it starts right up if I let it sit for few minutes.
Like I say, I'm leaning to injectors. Anyone ever hear of bad injectors from Jon?
I'm beginning to lean to the injectors I installed from Jon. I pinch the delivery line and it bleeds down, same with the return line. (I couldn't get it to duplicate the results I had starting the car and the pressure holding with the return line pinched.
Now I know it's a booger to get these lines pinched correctly but it would at least slow down.
The thing I'm bumfuzzled about is I get no smoke at start up and it starts right up if I let it sit for few minutes.
Like I say, I'm leaning to injectors. Anyone ever hear of bad injectors from Jon?
08-28-2010, 07:08 PM
#19
