Im running a 1991 TPI 383 and have been troubleshooting it for a few days now.......I could use some advice from you guys on here.It starts and idles just fine,with the engine cool it will rev up to like 2500 rpm and then bog.Then as the motor warms up a little it starts to bog anytime I touch the throttle.SO I assumed it was ignition related and tested the ignition coil,the pickup coil and took the module and had it tested.All good.Map is reading about 2v at idle,timing is set at 6* btdc and jumps to 19-20* once the bypass is hooked back up.O2 sensor is new,knock sensor is new.I am not getting any codes.The only code I got was a code 42 when I had the bypass unhooked for setting base timing.SO we checked the fuel presure and the fue pressure started out aboyt 43psi with ignition on car not running.AT idle it stayed steady at 35-38 psi,thenh when you try to go past 1/2 throttle it would drop to like 15 psi and lower.As the engine got a little warmer it eventually stayed around 15 psi and lower no matter what rpm,it got so bad that you couldnt touch the throttle and it would die......but it would still idle.SO we checked the fuel pressure at the pump and it jumped up to 90 psi.....so now I need to know if you guys think its a regulator problem or maybe some leaky injectors?Its got 24 lb injectors bought on ebay.they all ohm out around 13 ohms.I pulled the spark plugs and they werent fuel soaked........I am at my wits end.I ordered an AFPR so waiting on that but wanted to see if you guys had any other ideas?????Help me please!

 

I just read a thread similar to this. The final problem turned out to be one bad fuel injector and the fuel pressure regulator. Whether it's your problem or not, that I can't say. Hopefully you'll get it worked out soon.

 

Go the simple route frst -

Have you changed the fuel filter? These are classic plugged/or gettingf plugged up fuel filter symptoms......

 

Well i guess i should change the AFPR and then pull the rail up and check to see if the injectors are leaking anywhere?
Should they not leak at all or will it be noticeable if they leak?Thanks for your help,I was also entertaining the idea that it may be a combination of the two also......man what a pain in the butt!!


Anybody else have any ideas that i could check into?

 

Yes the filter has been changed......is there any difference in regulators between a 305 fuel rail and a 350 fuel rail.Mine is a 305 rail.....how much of a difference does that make?

 

Absolutely none.

Not to be **** or anything, but are you sure you put the exact right filter on there?

Ad that is was turned the right way? (it makes a difference)

 

I'm having the exact same problem with an 89 305 TPI setup . I have a new pump, AFPR and new injectors. I replaced the fuel filter and am now going to try and start at the tank pickup and work my way to the front looking for a restriction of some kind. Let us know if you find the solution to your problem, and I'll post mine likewise. FYI, My motor is in a 1985 Volvo 740 diesel body, makes for a great stealth car.

 

Well not to be a smart @ss but I have the filter in the right direction,I know you had to ask..........anyways IM getting a new regulator today so hopefully that would clear it up...
I dont think theres a restriction in the lines as I get a steady stream of fuel from the return line....at the tank, and I get 90psi from the pump....im just not building any pressure at the rail........
Theres no difference in a 305 and 350 pressure regulator?

 

Well changed the regulator and no change in the way it runs.....I have not put the gauge back on it yet but Im really discouraged by now....theres got to be something else Im overlooking.Is it possible that my new pump doesnt put out enough volume?I know its a 255 lph walbro external pump and for the heck of it I turned the fuel pump on via the test circiut and put the return line into an empty oil bottle,and in a minutes time it didnt even get 1/2 a quart of fuel bypassing with the engine off......is that about right?

 

This might sound silly, but you got enough gas in it?

Also when you pressure test how long will it hold pressure for?

Also have you made any chip mods for the 383?

 

Yep got gsa in it!I sent the chip out to Affordable fuel Injection and they programmed it for all my mods....I have not done a leak down test yet.Will try that one tommorow.
What would happen if you switched the pressure and return lines?Would the car even run?I know I checked that like 20 times but just to ease my mind Im gonna run em down again.......

 

any luck yet on a solution to this problem???

 

No, spent the evening following fuel lines and removing the pickup inside the gas tank looking for restrictions. I did get my fuel gauge to work though! Drove the car and the problem gets worse as it warms up. If I turn the afpr screw up a bit, the pressure jumps to 80 psi+ and kills the motor. Then I turn it down but have less power than before. I can easily get the pump to put out 80-90 psi pressure, so i don't suspect it at this time. What are the symptoms of a bad AFPR? How stable ahould the pressure be, at times my gauge needle swings rapidly over a 15-20 psi range, other times it's pretty steady. Mine seems to either work below 42 psi or above 80. seems wierd to me, although when it spikes to 80+ I can gradually watch the pressure drop as I turn the adjusting screw out. i'm just glad this is not my DD altough I would like it to be.

 

danclemts you might have a leaking injector causing the jump between pressures..

If you have a scanner slap it on there if not try below

Put the FPG on the car with it off, turn the key forward but not running, look at you pressure. should be 35 or so. turn the key off and watch for leak downs. should hold soild for 20 mins then it will slowly bleed off. should be easy as that.

good luck

 

I have no problem holding fuel pressure with key off, so I don't think its a leaking injector. I did discover that when the PO installed the BBK afpr he did not put the spacer washer on top of the spring. I can now adjust my fuel pressure properly, but still have the problem of losing fuel pressure while driving. If I let off the gas, pressure goes up, when I get on it, pressure drops. After a minute or two of driving the pressure will not come up and the car will barely move. If I shut it off for a few seconds, it will go back to normal pressure at low throttle and dropping under load. It really feels like a bad pump or a restriction in the feed line. The pump will go up to 80+ psi, so I am inclined to not suspect it right now, besides it is a fairly new walhbro. I have a combination of rubber and metal lines from the tank, maybe a hose is collapsing? Thats the next thing to check on my list. All the rubber lines I can see are fuel injection hose, but maybe theres a problem there. BTW I have a new clean fuel injected rated filter on the beast.

 

Well I found my problem..........as much as I hate to come on here and say it.I took off the inlet to my 255lph wal-bro external pump to find a beetle or june bug all wadded up inside the pump inlet............what should I do now?Can I consider the pump garbage?I hate to buy another pump but I dont want to put this all back together and it not work either..........thanks guys for all your help....problems like this one suck.

 

Well, if you can get the beetle out... I don't see why it would have broken anything. Just clogged it up. 3rd gen powered by bug guts... heh

 

Cool, clean it out and rev it up. I need to check my pump, I'm thinking the problem is somehow related to it also.

 

I've heard about alot of "buggy" software, but fuel pumps!
That's a first for me

The filter should have caught any legs (bug parts) so I'd think your ok to run with it.

 

yep first for me too