Well I got the fuel pressure regulator changed and the EGR changed and got it all put back together and it runs like absolute chit!!!!!!

Can't figure out what I missed. I have the fuel pressure cranked up pretty high. The screw on the regulator is in pretty far. So it should be getting plenty of fuel.

Anybody who has done this have any ideas?

Just out of curiosity, the vaccum hose that comes off of the fuel pressure regulator; should that be attached to the second hook up on the back of the plenum, right?

Here is a pic.

 

Could you be a little more specific. Idling rough? Surging? Pinging? All of the above?

 

Yeah sorry about that. That was a little broad.

It starts but stumbles real bad. Barely stays started. Runs rough and surges. That's about it.

I was wondering, after the fuel system is opened up to put in a new regulator, can it get air pockets in it?

 

Air pockets *should* get flushed out pretty quickly, since it's a cross flow design rail system.

Too much fuel pressure can definitely cause a rough running engine. So can a new EGR valve that is stuck. Check to make sure you got all the plug wires back on correctly while your at it. I'd probably first try lowering the fuel pressure (a lot, like back the screw most of the way out, except a turn or three). I'll assume you don't have a gauge. If you do get one, 43-44 psi without the vacuum line connected.

The vacuum line looks like it's on correctly in the picture.

 

hello

check the tps (throtal positioning sensor) and the fuel presure--also reset the computer for the spark control
If i remember right you need to have the motor running and then jump a couple terminals in the reader port

a chiltions for your car wil have the procedure mine is in the shop with the car at anothe location


later and

GB

rick

 

Thanks for the info guys. I also believe it is fuel related. Thats really the only thing I changed. The EGR valve was the same one I just cleaned it and redid the connection to the front of it. That screw in wire on the front kept backing out.

OK, I'll try backing off on the fuel pressure. I was doing the opposite. It started about 1/2 way in and now it's about alll t he way in. I'll back it off.

Rick,

The tps seems to be ok. Not throwing a code or anything. As far as resetting the computer for the spark control, I've never heard of this. I'll look it up in the Chilton's.

Pretty frustrating, I've never done this before by my self but thought I'd give it a try. And so now it won't run.

 

So when adjusting the fuel pressure, is the typical adjustment to turn up or turn down the pressure a few pounds made by 1/4 turn? 1/2 turn? 3/4, full turn? What have other people experienced?

 

This may sound a little pre-historic, but it's a lot like tuning a carb. Plug a vacuum gauge in one of the vacuum ports, then turn the regulator's pressure both higher.... then lower, until desired vacuum is reached (the computer might fight you a little.... but let it adjust to it).

 

Don't have a vacuum gauge. I should probably get one but I should probably get a fuel pressure gauge too.

 

You, uh, don't know what your fuel pressure is set to??

 

With OEM EFI systems, you can't exactly set the fuel pressure to whatever you want at idle to get the highest vacuum. You'll end up with 60 psi, and maxed out BLM. When closed loop is active, your pressure increases will be fighting a closed loop fuel reduction. Idle vacuum will be best around 13.5:1 A/F, but the computer keeps trying for 14.7:1, until you hit the lower limit of block learn and integrator.

EFI really likes to know that the fuel pressure is close to perfect, in basic terms. It dictates how much fuel is injected in each pulse of the injectors.

 

You could try adjusting the fuel pressure while datalogging and watch to see when it changes from rich to lean.
Might get you closer than you are now without a gauge.
Then leave it slightly on the rich side so there would be enough pressure if you get on it alittle.
Wouldn't suggest any WOT until you know what it is set at and the bin is changed to match.
Jp

 

When you learn more about TPI, you'll find that in closed loop mode, the ECM cycles rich/lean several times a second...

 

The problem is the fuel pressure regulator. I have the same brand and without the screw in at all, the pressure is at 50lbs. If you have the screw cranked in alot, you are looking at about 60+lbs, way to high for the stock settings.

Try taking the screw all the way out and then see if it runs and clears it up. If you have an old car with TPI, you must have a fuel pressure regulator to keep it tuned up. You might as well add one to your tool collection. You can get them at autozone for $35. Make sure the one you get works with the TPI or MPFI for our cars.

 

I think Maroon is right. But here is my problem, that screw is really really long. I have back it out as far as I can. It is actually hitting the plenum and needs to come out more. I thing I will cut the screw in half and get it out the rest of the way with needle nose pliers. And then try to put in a shorter screw. It will be a tight fit but might bre possible. If I fail, then I'll have to take the plenum off again. Which is what I was going to have to do anyway.

 

No no, I agree with you here. What you're saying can also apply to the idle speed screw itself... if he were trying to set desired RPM by turning it in or out with the engine running, and IAC plugged in, the computer would constantly play tug of war with him, because it wants control.

 

I meant to watch the BLM's and INT and see when the changes reflect the correction due to the fuel pressure.
When the pressure is too high, the BLM will pull low to decrease the fuel, Once he hits the sweet spot and continues they should revese and begin to add fuel.
This should get the thing running close without a gauge to really know.
Better than nothing.

 

The only problem with datalogging is that it does not want to run at all. It will only idle for a few seconds before it quits.

 

So tell me if this sounds fishy....

Decided to take the new fuel pressure regulator and put the old one back on. Now when I originally took the old one off it sprewed a little fuel. Totally expected. When I took the new one off tonight it did not spew any fuel.

So what is an easy way to check and see if the fuel pump is delivering fuel. It's only a little more than a year old so I do not expect a problem there. But it is worth checking.

 

I guess buying a fuel pressure guage is out of the question??

 

Yeah, you have to cut the end of the screw off or go to the hardware store and find a matching one that is shorter. I don't know why they have one that long. I can promise you though, it is your pressure. Either get a gauge or go find a much shorter screw that you can put in with the intake and everything already put together.

If you can't turn it, then it is not a tuning aid and otherwise just taking space or worse, hurting the engine. In other words, just do it correctly and not half-as$ed.

 

OK.

Took the plenum off again and put the old pressure regulator back on. Will put it back together tonight. Keep your fingers crossed.

 

 

I also have to third this. If you are running too much fuel, you could wall wash the cylinder walls and start tearing up the motor. Just spend the $30 or borrow one from a friend.

Daniel

 

Not to discourage you from buying a pressure gauge, but most of the cheap ones are ABSOLUTELY HORRIBLY INACCURATE, like 5-10 psi off on some. Buy or borrow a nicer one.

 

UP AND RUNNING!!!!!!!!!!!

Seems it was the new fuel pressure regulator I put on. I'm not sure what was wrong with it but I put the old one back on and put in a longer screw for adjusting. It's longer than the original but shortrer than the one in the screwed up regulator. So it fits under the plenum and still leaves me enough room to adjust.

Thanks one and all for your help.

 

Though you switched your afpr, you should still buy a fp gauge and a scan tool to read blm's

 

A scan tool will read blm's? I didn't know that!!

 

OK, so finally got it running and now its throwing a code 22. Looks like a TPS.

So I go and buy a multimeter ($30 AutoZone) and do some research on adjusting the TPS. I come up with this page:

http://www.iroczone.com/techarttpsadj.html

Sounds nice and simple. So I start by putting the battery in the multimeter and probe the proper two wire of the TPS and nothing. No reading on the multimeter. OK so lets try something that I know is good like the battery since the car starts just fine. Touch the probes to the appriate battery terminal and nothing. Won't even register the battery voltage.

So it will be back to AutoZone with a bad multimeter.

Don't you just love the way my live works.

 

Welcome to the wonderful world of Hot Rodding. All of us go through the same exact thing, you're not alone, believe me.

 

Yup...TPS voltage too, among other things...

 

Yeah, I bought it for the TPS voltage. I took it back today and got another. Hopefully this one will work. I'll try it tonight after work.

 

Ok. Finally got a multmeter that works and probed the TPS and it read .62v. Adjusted it to .54 volts and took it out for a spin. Seemed pretty good at first put then got another code 23.

I think it's time for a new TPS.

Opinions?

 

probably a wire rubbed through somewhere. Trace as much of it back to the firewall as possible. Check near valve covers and exhaust manifolds. Check at the connector too. Only then try a new TPS.

 

OK. I should also check the grey wire for 5v.

 

You, uh, might want to check into the difference between a scanner and a multimeter.

Scanner hooks up to the ALDL port and reads the data stream generated by the ECM.