No power after 3000 rpm, Like it's not getting gas Options

[silverteener]

My dad and the guy that rebuilt my motor finally got the timing set on it today but it still doesn't have any power after you get to around 3000 rpm. (IMG:style_emoticons/default/WTF.gif) It's a 1.7 and fuel injected. Tomorrow they are going to check the fuel pressure and swap out the MPS for another one I have sitting on the shelf. Any ideas why this thing won't run??

Thanks

Scott

[r_towle]

the timing is wrong.

RIch

[TravisNeff]

check your valve adjustment too.

[byndbad914]

(IMG:style_emoticons/default/agree.gif) especially about the timing, easy check and if you still have points ignition check the settings again.

sounds weird, but just double check your plugs and make sure they are the right ones. It (honestly) wouldn't be the first time I have seen a new motor with new plugs and just accidentally bought the wrong plugs.

[charliew]

I once got a set of points that it took me two days to decide the spring was weak and the points were floating at about 4k. It obviously happened after I changed the cap, rotor, points, condenser, plugs and wires but it was running rough before I started. I even wasted money on a new coil trying to fix it.

[ericread]

If you're still having problems with this, you might just want to replace your distributor cap. Sometimes the cap will develop a crack you can't hardly see. But at the higher RPMs, the cap crack will widen, causing the timing to fail.

It's pretty cheap to change out the dist cap, so what the heck. give it a try...

Eric

[silverteener]

Thanks for all the suggestions. I stilll need to get a timing light and recheck the timing. I did test the fuel pressure and it was around 35 at idle. I also checked it while driving it and at around 3500 rpm it drops to around 20 or lower. I also noticed that if I don't give it alot of gas it powers thru the 3000-4000 rpm range. Only when I really try to give it gas that is bogs down. Hopefully resetting the timing will fix it. It will be a couple days before I can try. Thanks again.

Scott

[charliew]

It really sounds like a fuel supply problem if it trys to speed up as you are letting off or gradually mashing down on the pedal.

[swl]

I did test the fuel pressure and it was around 35 at idle.

That's a little high Scott. I think 28-29 is the spec. High pressure = rich running.

Another area to check is the advance plate in the distributor. Make sure it is moving freely.

[silverteener]

how do I adjust the fuel pressure? It did smell like gas when I was driving it but I didn't find any leaks. the advance plate was sticking before they put the distributor back in but they took it apart and fixed it. Is there a way I can check it also?

thanks

Scott

[swl]

fuel pressure regulator is the next piece downstream of the drivers side fuel rail. Undo the locknut. Counter clockwise to decrease.

Haynes Chapter 2 section 4 (IMG:style_emoticons/default/wink.gif)

[swl]

It did smell like gas when I was driving it but I didn't find any leaks.

This can be serious Scott so don't ignore it. Rich running shouldn't be smelt in the cabin - if you smell gas you have a leak or at least some weaping going on. A new to you car should have all the rubber hoses replaced. Minimally the high pressure ones but best all of them. It will only take a weekend but well worth the peace of mind. Most likely culprit for smell is the line between the tank and the steel lines running through the tunnel. You have to remove the tank from the car to replace them so they frequently get forgotten. If they are still the originals they will be leaking - not huge but enough to stink.

[silverteener]

I will check that! All the lines at the back are all new. It would have to come from up front. Thanks again.

Scott

[silverteener]

I adjusted the fuel pressure last night. It was pretty easy actually. It did change the idle a little and now it cuts out at all rpm ranges. I'm going to reset the timing tonight and hopefully that fixes it! I'll have to read up on timing again. I haven't done that in a while!

[silverteener]

I set the timing again tonight and it is still not running right. I also changed the fuel filter and rechecked the gap on the Petronix. I can drive around fine if I don't try to get on it at 3000 rpm, if I do it falls flat on its face. The valves were set when it was rebuilt and rechecked before the motor went in. I haven't check them since though. I also need to check the advance plate on the distributor, I'm just not sure how to do that yet.

Before when I had the fuel pressure gauge on it and was driving around it dropped down to 20 or below when I got up to 3500 rpm. Is this normal? My dad is thinking the fuel pump is not working right, could that be it? Is there a way to test the fuel pump? (IMG:style_emoticons/default/confused24.gif)

I'm going to drive it for now and hopefully we can figure this thing out. You guys have a lot a great input and I'll keep trying suggestions.

thanks

[charliew]

It's not getting enough fuel if you can let up and wait for it to get going. You either have a restriction going to the regulator or the injectors or the pressure is too low to feed enough volume to the injectors. You might have a tps problem but I would make sure the fuel supply is good first. When you first open the throttle the vaccum goes down and the map or maf says there is a lot of air so increase the fuel to even the mixture out. The fuel pressure regulator is usually what increases the fuel supply by reducing the return volume. I'm not educated on the various 914 fi systems but I'm just going by other fi systems. The thing is I wouldn't drive it too much as it is probably really lean when it is sluggish.

[silverteener]

I lowered the fuel pressure to 29 but it was at 35 and still did the same thing. After I posted last night I got to reading more of Brad Anders info and one thing I haven't checked is the throttle switch. It was taken off when the engine was rebuilt. I found a great article on Pelican on how to check it and I'm going to work on it tonight. It does seem like a fuel problem but I have all rebuilt injectors, all new hoses in the back, a new fuel filter, and I've set the fuel pressure. The only thing I haven't done is try another fuel pump but I don't have another one to try that works. Hopefully the throttle switch is not set right. I will know more tonight.

Thanks!

[underthetire]

A quick check is to unplug the air temp sensor. Thats kinda a old school way to fatten it up. If its better, you have a fuel problem. I wouldn't use this as a fix, as you are too lean to be safe.

Also, make sure you have the advance and retard vac lines correctly hooked up on the dizzy.

[naro914]

Check your fuel filter, and check the rubber fuel lines under the tank....

When we bought Papa Smurf way back when he was stock 2.0, we drove him from Denver to NJ. We had problems running up above 3000 rpm somwhere in Iowa, and we started to notice it really became a problem with a full fuel tank. We stopped at a service station, had the tank drained, pulled it, and found a crimped/weak fuel line. Replaced it and all was fine.

Now, fast forward to last year. Club Racing, I'm running well at Road Atlanta all weekend, and all of a sudden 3 laps into the enduro, I head up T1 and the car bogs down at full throttle. Once I get on the brakes, back and forth, it's fine, until I'm back on full throttle out of T5, then the back straight....

We spend months chasing plugs, wires, coil, rebuild carbs, etc until we check the filter and find it filled with gunk (no idea how since we run 110 race fuel). Works perfect ever since.

[SUNAB914]

Your pertronix could be failing, just about the same thing happened to me. It will get worse. I went back to points. Through in points and condenser and see if that fixes it. Cheap and easy.