seems when i push the engine hard it will suddenly lose power. like it's starving for fuel. doesn't stall but can't get above 2000rpm's or so and it backfires a little. when i take it easier it comes back and runs fine. do fuel pumps get weak or is it a work or not work type of thing. sorry about the typo

I kinda like the typo....
Do ya know if the valves are correctly adjusted? 2000 is pretty low to be running low on fuel volume. Maybe the filter is clogged? Has the car run right in the past? Did this hit alll at once?

I can't really answer you question about whether a fuel pumkp can get 'weak' or not because I don't know. However, it sounds like you're just getting behind in your fluel flow, as if you don't have the capacity to push it too hard, right? My pop's having the same trouble with his motorcycle right now. I would first check the main feed lines to make sure they're not clogged up as well as the fuel filter. If it turns out not being that or the pump, I might take a look at the enrichment valve. 2000 RPM sounds a little low for it to be needed, but I'm still new to this injection system. I'm just throwing some things out there as if I knew what I was talking about. Don't mind me.
Mark D.
Oh yeah... Did this start happening all of the sudden, or has it been a gradual loss?

this problem started today before couldn't get above 4000rpm's and would stall constantly. have new fuel lines,vacuum hoses dizzy, cht, timing and dwell. this problem is a major improvement from last week. gonna do valves next and put in a new fuel pump. just wanna make sure i'm on the right track

You are really battling this thing! Glad you are making progress....I'd check those valves asap...

I would definately check the fuel filter before you spend the money to replace the pump. It's possible that the pump is getting weak, but rather unlikely. I would also run a bottle of injector cleaner through it once you get it driveable.
Another possible thing to check would be the fuel pressure. Since the D-jet is a closed loop system with no exhaust feedback, the computer's going to set the dwell time on the injectors based on manifold vacuum (I'm explaining because I don't know how much you know) no matter what the final mixture turns out to be. That dwell time is based on 28 PSI fuel pressure. So if you're getting less than 28 PSI, then you'll be getting less fuel for the same dwell time. There's a port on the driver's side fuel rail to check this with a pressure guage. If your fuel pressure is low, then there's probably a clog in the pump, filter, feed lines, or regulator. If you have good fuel pressure, then it's probably a problem with the injectors or more likely with the vacuum signals being sent to the black box.
Just might be somethiing to check to help narrow the problem down if you get stumped. Still, I'd check the filter first. Hope that helps.
Mark D.

filter is new and clear. pressure at the rail was 30 psi i believe will check again. lines are new vacuum hoses are new how do you check if fuel filter is clogged? also valves haven't been done yet

I have had good sucess with removing it ant tapping it on the proximal end.

If it is clogged mucho debris will fall out -probably rust

BTW your pump went out tuesday.

Just thinking could it be a bad accelerator cable, if the throttle is not
working right. you would not be getting full power. if you buy all
new parts you will fix it sooner or later.

Robert21

Have you changed the air in the tires lately or maybe it's a bad gas cap. I know

change your CD in the player. Just undo the fuel cap, lift and role a new car under it. Sorry.

had accelerator assembly rebuilt by kos auto in montclair n.j. (that's way beyond my ability) put on new tires already. rolling a new car under the gas cap is the best idea i have heard so far but unfortunately all the good 914's seem to be in cal. by the way is it true that in so. cal. mps's grow on trees, that they sell fuel pumps at the local markets and you have rolling fields of rust free longs and pristine heat exchangers? seriously thanks for the help guys

Hey Man,
If you can get a fuel pressure tester and hook it up you should check the pressure under load. If when you give it gas you see your pressure drop then that is a sign that your regulator or your pump are kaput (provided your filter and lines are good to go). You do know that there is a filter sock INSIDE the gas tank, right? If it is getting clogged with rust.....well, you get the picture.

This is all based on your previous diagnosis of fuel pressure. It could also be a TP sensor or other sensor problem if not FP.

took out the tank and cleaned and re-epoxyed it when i got the car . lines seem to be clear no junk building up in the filter. stupid ? what is a tp sensor?

Sorry, it is a toilet paper sensor



TP= throttle position sensor which is located on the throttle body. If it is worn you can have similar symptoms, but it is usually only in a spot of the RPM range and not the whole thing.

Oh ya, points gap? I would definetly adjust the valves and points gap as a starter. If those are out then they could mask another problem.

You will beat this, you are on the right track and asking good questions.

Yup, you're definately asking the right questions. I'd say most likely it's in your fuel supply from the symtoms that you described, but possibly an issue with the injection itself; IE TP sensor, AF sensor, ECU, ect. Just keep eliminating things one by one 'till you find it, and you WILL find it. Good luck and let us know.
Mark D.
Tip: get a manual and crosscheck the vacuum lines with the diagrams to AMKE SURE everything's hookd up right. Again, I'm only saying this because I don't know how much you know.