fuel pump pressure

[bscoffey]

to whom,
I installed a 03 & up spider injectors (had a few leaky injectors). Do I still need the 62-64 psi @ start up since the new spider has mini injectors on them? Just wondering.

[bscoffey]

[ihatemybike]

I believe CFI and MFI both require the same pressures. The numbers you state seam right for starting with mid 50s for running.

Are you having trouble starting?

[bscoffey]

no just when pulling a hill it drops down to passing gear and the ses light starts flashing. I know this means missfire and the last time i had it scanned it showed misfire on all cylinders. I have put a new distributor,wires ,plugs,cap, rotor & coil. I dont like just changing parts but I have no other choice . i still have the misfire problem. I thought it might have low fuel pressure but its running around 58 to 60 psi while going down the road. i dont think the fuel pump is the prob but u never know.

[bscoffey]

[ihatemybike]

Have you tried Seafoam and/or GM Fuel System Treatment Plus?

[rev_les]

Something's definitely amiss there. My '99 with 3:73's gets better mileage than that even in stop n go city driving.
*edit* did you ever get the distributor situation straightened out??

[bscoffey]

hey rev les,
Sorry it took so long to get back,computer problems. I replaced the distributor ,matter of fact i replaced all the ignition:dist ,plugs,wires ,cap rotor,coil. nothing helps. There is still alot of play in the dist as far as movement in the block.there is hardly any movement in the rotor as far as rotational movement (turning the rotor clockwise and counterclockwise). I still have a knock in the eng but only at a 1200-2200 rpms.nothing at idle or at higher rrpms. Im still leaning toward the transmission though. Had it rebuilt last year and not too sure about the rebuilder. The trans dosent shift like it should especially in tow-haul mode. Has a deffinate problem in second and a shift problem going from second to third;like it take a second longer to shift ,kinda like a small hesitation between second and third. I think that might be where the rattle or knock is comming from.The rebuilder also put a lower stall converter in when he done the rebuild along with a tow kit in the trans. I think that may be some of the problem. I reall dont think that this trans needs a shift kit because of the tow-haul but he said it would help.also i dont think the converter needs to be lower because it is keeping the engine from gettin into the proper torque range before taking off. maybe im reading too much into this and maybe im not , im just tired of getting 12 mpg . I have tried to resolve these problems but i belive im at the end of my rope. Im currently looking for a replacement vehicle and it wont be a chevrolet. I hate to be that way but this van has put a bad taste in my mouth for gm products. And i can now see why they filed for bankruptcy protection. I would have expected something like this van to come from china but not from the USA. We used to take pride in what we built but that way of thinking must have been traded for the lure of the dollar. I must be old fashion but if i make a mistake its my job to take responsability and fix it not to sweep my mistakes under the rug and hope they will go away. My way of thinking is to do it right the first time then you wont have to worry about it later on. I'm rambling . I do think alot of the problems could have been dealt with at the factory before these vehicles left. Like the sunshell problem, the rod bearing problem, the poppet problem, the dex cool problem etc. Stop being cheep , stop building junk take pride in what you build , start selling good dependable vehicles and kick the government out on their buttocks!!! nuff said

[astro355]

And completely agree with you about the problems that they should have fixed but I don't think any of GM's failures there have much to do with your current situation. A misfire is caused by the a faulty ignition, a problem with the air/fuel mixture or a loss of compression. Diagnosis is key here, not throwing parts at it. The transmission "problem" is more than likely a result of the engine problem. You're complaining of poor fuel mileage and also have a knock in the engine. Have you performed compression tests on all cylinders?

Here's a link that may help:
http://www.aa1car.com/library/misfire.htm

[bscoffey]

I have performed a battery of test on this engine just short of a complete tear down and rebuild. i have performed a compression check and all cylinders were 170 psi. The transmission problem started out with a sheared sunshell (defect from the factory). The next problem was the poppets were not working properly(bad design from the factory). The next problem was leaking intake gaskets( a problem starting with the DEX COOL and they tried to do a band aid fix with plastic intake gaskets,like thats gonna work ,come on plastic ,that breaks over time, between the intake and head where the majority of the heat from the engine is generated also bad design from the factory). Now i'm pretty sure i have a balance shaft problem ,the rattleing in the engine, and the service bulitin wants me to put a tensioner on the timing gear,another band aid fix for a bad design(from the factory). I can go on and on .What i'm saying is if a poor job is done then fix your mistakes.I'm self employed and when i do a job i do it right the first time.If i have to go back for a problem with materials then i fix it ,no charge. I have never had to return for a workmanship problem. If i ran my business like GM i wouldn't be in business long and i dont think the us government would bail me out. I have said it before i really dont have the money to work on this van any more.
As far as diagnosis goes i have diagnosed all of these problems before i replaced the part. The only thing is (like i have been saying over and over again) something else screws up!! And when i get everthing fixed it will start all over again. This one has a very bad case of gremlins. If i Could trade it i would but the car lot wont give me but 1500 bucks for it so i guess i'll drive it till it quits then rebuild it.

[astro355]

170 psi sounds high to me on a 4.3L. How many times did you crank the engine to get 170 psi on each cylinder?

[bscoffey]

maybe 5 sec . enough to get it to turn a couple of revolutions. i have a new question . I have had a misfire but if it turn on the tow/haul switch the misfire vanishes.i turn it back off and the misfire returns. all this happens while going uphill @ wot. with the t/h switch on it runs fine like it should ,strong and fast.with it off it stumbles sometimes and is sluggish especially when the t/c locks up . If i hold the brake lightly to keep the t/c from locking up it does a little better.