Can't boost! Tried all I can think of

[nightwalkerancestery]

Ok, so this has been going on for a little over a month. A couple months ago my FPR went out. I finally replaced it with another stock one that was said to be good. It ran fine again... for a couple weeks. Then I got a small hiccup here and there. Not too much to really worry about. But then it got worse... and worse... and worse. It's leveled off where I'm at now.

 

Here's what happening: the car runs perfect and accelerates perfect and cruises perfect as long as I stay in vaccume and stay below 3.5k rpms. I can boost quickly to 10psi but not for more than about 2 seconds before it starts to misfire like CRAZY! I can't go more than 1psi without it backfiring and me having to get out of the gas to get in vaccume for it to smooth back out. It progressively got to this point, mind you. So I've spent the last week trying to find the problem to no avail.

 

Here's what I've done:

 

1. Checked/Corrected Valve lash (Mech Rockers)

2. Checked cam and crank timing [perfect]

3. Checked dizzy timing [perfect]

4. Checked cap and rotor [a little arc residue, but cleaned and no change]

5. Checked wires [all spark well]

6. Checked plugs [no unusual build-up but they did look a little white] [reset gap at .035]

7. Checked compression [125,120,125,130] (rebuilt engine only 10k miles ago so the 130 might just be build-up)

8. Replaced Injector Clips about 7k miles ago

9. MSD 2 Blaster Coil put in about 2 years ago but appears to be in good working order. To check I put in the stock coil which was good when replaced and no change.

10. Installed aftermarket RRFPR and Pressure Gauge

11. Injectors were cleaned and flowed about 5k miles ago and to make sure I had a friend tap the ignition and put the primary clip on each injector and they didn't leak, nor have a bad spray. They sprayed fine and was an even mist!

12. Checked for boost leaks and found none

13. Replaced all vac lines about 20k miles ago and did a vac line clean-up at the same time

14. Did a full TPS/ISC reset

 

There is a small exh leak from the hed to manifold flange due to the gasket deteriorating from exhaust. Stupid nut backed themselves off and a few were loose and some GONE! They were torqued properly but the "flanged locknut" obviously didn't do its job in LOCKING! But this problem was before everything went downhill and had been temporarily resolved. To make sure, a new gasket has been ordered. I need one anyway There is one catch, however! I can unhook the FPR and run at full volume and it runs GREAT at all rpm's and full boost alike! Other than the gasket, I'm baffled! While writing this I got a hunch that maybe the secondary clip isn't working properly. Maybe the connection broke somewhere or something. I'm going to check on that as soon as I get home from work today.

 

All other suggestions VERY appreciated!

 

- Charles

[boneTSI]

I have this exact problem it's even going on for months now

[Caliber308]

Check your Fuel Pump and Vacuum Advance out.Just having the Fuel Injectors cleaned and flowed doesn't mean JACK. I had my Stock FIs cleaned and flowed years ago....the Secondary lasted appox. one month before it was stuck wide open causing the car to miss,spit and sputter at 2500 to 3000 rpms due to a Rich condition. Do you have a reliable FPG installed? A Wideband gauge? The Wideband will tell you whether or not you have a lean or rich condition real quick.

 

Bill

Edited October 24, 2012 by Caliber308

[nightwalkerancestery]

Fuel pump is a Bosch high flow and is still pumping as good as when I got it. Vac advance was replaced about 5k miles ago and holds vaccume. If I suck on it it'll advance timing like it should.

 

I understand this but I've replaced all my fuel filters too and checked them again and again and still no change. Injectors were cleaned VERY thoroughly and the guy LOVED the spray pattern. I've taken them out and pressurized them with a hose filled with cleaner and a compressor nozzle and I pulsed them with a 9v and they spray perfect and not a single dribble from either. I have a rising rate aeromotive set at 35psi at idle. No, I don't have a wideband OR a narrow band and there's NO way I can get one any time soon. I'm dirt poor right now. Work is slow and bills need to be paid but my car needs to run or there won't be a job. One thing to note though is that when I pulled the plugs they were pretty white. They weren't really a light whitish brown like they should be. But that was before I put in the aftermarket FPR. Oh, and it has an aftermarket Bosch single wire o2 sensor. I'm still totally stumped...

 

Honestly, could a turbo in need of a rebuild/new bearings cause this? I don't hear noise from the turbo but I know it needs bearings. I have a friend that owns and runs a machine shop machining me out some bearings for it for my lack of money and his ability to make them. And yes, he's using the correct material and the correct diameters. Just in case that was going to cause me to get hounded...

 

I have this exact problem it's even going on for months now

 

It's SO annoying! And it disheartens me since I can't boost and what's worse is that it seems to be hurting my MPGs quite a bit

 

- Charles

[nightwalkerancestery]

Somebody PLEASE give me some input. I'm desperate. I can barely afford gas as it is with bills and all and if it's hurting my gas mileage then it's going to be even harder. I still can't figure out the problem for the life of me.

 

- Charles

[StarquestRescue]

There is one catch, however! I can unhook the FPR and run at full volume and it runs GREAT at all rpm's and full boost alike! Other than the gasket, I'm baffled!

Than it's pig rich with the fpr hooked up. Possible causes would be a boost leak.. The check is to pressure rise the intake track from turbo to tb with say 15- 20 psi and see if you find a big leak. In your case since the problem start at very low boost it would be a pretty big leak, like a hose that's off a pipe but looks ok.

 

What is the base pressure, maybe you could turn it down a little?

 

An ignition problem is a possibility , but that usually shows up further in to boost.

 

At about zero boost on a 87-89 the car transitions to both injectors so the secondary, secondary wiring or ecu is suspect, but documented ecu failures are rare.

 

Does not sound like a turbo problem to me it it runs under boost with less fuel pressure (regulator disconnected).

[apate]

Try this disconnect your secondary injector clip and see how it runs.

If it runs the same secondary problem

Another thing to try is swap primary and secondary clips see how it runs

 

[apate]

I was just looking in the noob Q/A and saw a low boost post

Are you running the stock pre cat?

clogged?

 

[nightwalkerancestery]

Ok, so I have a new diagnosis. I tried to rev it up at idle. It seems that if I slowly bring up the RPMs then it runs smooth up to about 4k-4.5k. But, if I rev it quickly (pedal to the floor) then it sputters and misses at about 3.5k which is where my problem lies.

 

Than it's pig rich with the fpr hooked up. Possible causes would be a boost leak.. The check is to pressure rise the intake track from turbo to tb with say 15- 20 psi and see if you find a big leak. In your case since the problem start at very low boost it would be a pretty big leak, like a hose that's off a pipe but looks ok.

 

What is the base pressure, maybe you could turn it down a little?

 

An ignition problem is a possibility , but that usually shows up further in to boost.

 

At about zero boost on a 87-89 the car transitions to both injectors so the secondary, secondary wiring or ecu is suspect, but documented ecu failures are rare.

 

Does not sound like a turbo problem to me it it runs under boost with less fuel pressure (regulator disconnected).

 

the plugs would show it running rich. But they were nice and clean. No wetness from fuel to be found.

 

The base pressure is 40psi. I know the stock pressure is 35 but I set it at 35, replaced the filter, then it went to 40psi and i haven't gotten to resetting it yet.

 

the wiring seems to be fine. I rechecked all connections and I don't suspect the harness to be at fault. I unhooked the secondary and the change was drastic. So, I don't put the secondary wiring or harness at fault or even the injector. I haven't tried my 89 computer yet though. I suppose I could do that this weekend if not solved this evening.

 

Try this disconnect your secondary injector clip and see how it runs.

If it runs the same secondary problem

Another thing to try is swap primary and secondary clips see how it runs

 

I unhooked the secondary and the change was obvious. It almost died from the lack of fuel. I didn't swap the connectors though. I don't think the injectors or clips are at fault on this one. Everything has checked out.

 

I was just looking in the noob Q/A and saw a low boost post

Are you running the stock pre cat?

clogged?

 

Look in my sig I gutted both cats YEARS ago. Makes the old girl a lot louder though!

 

Still looking for help. Hopefully the new finding will spark input...

 

- Charles

[nightwalkerancestery]

Another thing to quickly note...my voltage is irregular as well. It fluctuates quickly between 14 and 15 at idle and it fluctuates between 13 and 15 when quickly revving at idle. But, under a load at all throttle conditions as well as easing into the pedal at idle, the voltage is stable between 13-14 without any quick, heavy fluctuations.

 

Could this cause a malfunction anywhere? It has never gone to 16v. But I didn't know if this caused anything. It has been like this for about a year and the car ran perfect under these conditions for so long before this. But it's just another thing to mention.

 

- Charles

[StarquestRescue]

What were the results of the boost leak check? How did it act when you turned the fuel pressure down?

[polarisman14]

That's better than mine, it's usually12 to 13. I think your issue is secondary fuel injector. I thought my turbo was stuck or something but that wasn't the case. Primary fuel injector controls vacuum to 0psi and secondary is your fuel in boost. That's my guess, if nobody else suggested it.

[Skullzaflare]

try swapping injector clips, it should idle on the green injector, though low and rich, and see if you can slowly rev it. sounds to me like its locking open

[nightwalkerancestery]

What were the results of the boost leak check? How did it act when you turned the fuel pressure down?

I didn't find any leaks. So that's ruled out. I haven't pulled the pressure down though. I haven't had time. But would the 5psi make that much of a difference?

 

That's better than mine, it's usually12 to 13. I think your issue is secondary fuel injector. I thought my turbo was stuck or something but that wasn't the case. Primary fuel injector controls vacuum to 0psi and secondary is your fuel in boost. That's my guess, if nobody else suggested it.

 

That's true but it seemed to spray evenly and didn't leak. I could try running it through cleaner again and pulse it some more to watch what it does...

 

try swapping injector clips, it should idle on the green injector, though low and rich, and see if you can slowly rev it. sounds to me like its locking open

 

I'll give it a try in a little while if I can find a light. I was thinking it was dirty again but it sprayed evenly and didn't leak. I would think that if it was sticking/locking open then it would leak.

 

In addition, would it make it miss/stutter when revving it in Neutral? I've never gotten it to boost in idle. It always shows at MAX at 0 right at vac/boost. But never goes into boost. So I don't know if the secondary even cuts on. Anyone else know?

 

- Charles

[apate]

Ok, so I have a new diagnosis. I tried to rev it up at idle. It seems that if I slowly bring up the RPMs then it runs smooth up to about 4k-4.5k. But, if I rev it quickly (pedal to the floor) then it sputters and misses at about 3.5k which is where my problem lies.

 

 

Bad TPS?

[nightwalkerancestery]

Nope. Have two of them that both check out good. And to make sure, when I did the TPS/ISC reset I set it to exactly .5v and I opened and closed the plate slowly each way and it was steady voltage all the way up and down. Not a single jump or dead spot.

 

BUT! Just switched the clips to see how/if it ran. Couldn't even start it. So I gave it a little throttle and got it started but it was so bad it sounded like it was running on only one cylinder. So I shut it off and just got back from the store. I'm gonna go ahead and clean it out the best I can and I'll do both while I'm at it. I'll let everyone know how it turns out.

 

- Charles

[Skullzaflare]

I didn't find any leaks. So that's ruled out. I haven't pulled the pressure down though. I haven't had time. But would the 5psi make that much of a difference?

 

 

 

That's true but it seemed to spray evenly and didn't leak. I could try running it through cleaner again and pulse it some more to watch what it does...

 

 

 

I'll give it a try in a little while if I can find a light. I was thinking it was dirty again but it sprayed evenly and didn't leak. I would think that if it was sticking/locking open then it would leak.

 

In addition, would it make it miss/stutter when revving it in Neutral? I've never gotten it to boost in idle. It always shows at MAX at 0 right at vac/boost. But never goes into boost. So I don't know if the secondary even cuts on. Anyone else know?

 

- Charles

where as it wont see boost free load reving it, after 1/3 throttle secondary injector starts to kick. same after 3.5k, thats why if you slowly rev it barly touching gas, you can actualy go to red line. something is happening when the secondary kicks in, be it in the injector clip (loose pin or bad wire, or something in the injector clip harness (replaced clips connection to old harness)

[Skullzaflare]

Nope. Have two of them that both check out good. And to make sure, when I did the TPS/ISC reset I set it to exactly .5v and I opened and closed the plate slowly each way and it was steady voltage all the way up and down. Not a single jump or dead spot.

 

BUT! Just switched the clips to see how/if it ran. Couldn't even start it. So I gave it a little throttle and got it started but it was so bad it sounded like it was running on only one cylinder. So I shut it off and just got back from the store. I'm gonna go ahead and clean it out the best I can and I'll do both while I'm at it. I'll let everyone know how it turns out.

 

- Charles

thats because its running rich, since the computer doesnt know there is a 1050 in the 650 place. if you hold the throttle a little more open it should clear out a little bit.

[ColdScrip]

Ok, so I have a new diagnosis. I tried to rev it up at idle. It seems that if I slowly bring up the RPMs then it runs smooth up to about 4k-4.5k. But, if I rev it quickly (pedal to the floor) then it sputters and misses at about 3.5k which is where my problem lies.

 

This points towards the secondary injector in my opinion. If its a boost leak, turbo, whatever you wanna point a finger at, then why exactly does it run fine with the FPR taken off? I'm guessing here but here is my guess: The secondary injector is not pumping out enough fuel (perhaps slightly clogged?), and with the added pressure with running without the FPR it now forces enough out.

 

Your problem lies exactly when the secondary is suppose to do its job. However things are fine with your FPR off. This should point to injector or FPR imo.

[Skullzaflare]

This points towards the secondary injector in my opinion. If its a boost leak, turbo, whatever you wanna point a finger at, then why exactly does it run fine with the FPR taken off? I'm guessing here but here is my guess: The secondary injector is not pumping out enough fuel (perhaps slightly clogged?), and with the added pressure with running without the FPR it now forces enough out.

 

Your problem lies exactly when the secondary is suppose to do its job. However things are fine with your FPR off. This should point to injector or FPR imo.

this reminds me of when i first got m shetland beige quest

it would sputter with a black and green unless fpr was unplugged (when i got the car (iits a 87) it had 2 blakcs, a 450 and a 650) when i swapped for the correct injectors it did this. turned out mine had either a non turbo MAF or it was bad, after swapping MAFs it went away.

 

do you possibly have another MAF you can try?

[ColdScrip]

this reminds me of when i first got m shetland beige quest

it would sputter with a black and green unless fpr was unplugged (when i got the car (iits a 87) it had 2 blakcs, a 450 and a 650) when i swapped for the correct injectors it did this. turned out mine had either a non turbo MAF or it was bad, after swapping MAFs it went away.

 

do you possibly have another MAF you can try?

 

You know this is a good point. If the ECU is tricked into thinking it needs more fuel then it ends up running very lean until you remove the FPR which allows more fuel to enter because of the higher pressure. If the MAF (or anything else that could affect the ECUs determining of the mixture) gives a bad signal then I could also see your symptoms.

[nightwalkerancestery]

Coldscrip and others are correct in assuming it was the secondary. It seems that it was flowing fine at base pressure but when it was increased, the clog showed. The secondary was partly clogged and wasn't putting out enough fuel. I just took both out, cleaned them with carb cleaner a couple times forwards, backward, and forwards again, then ran gas through them to "lube" them back up and popped them in and the problem is gone.

 

I would suspect rust from the tank that wasn't propperly disposed of when it was cleaned. The remaining rust was what caused me to have them sent off BEFORE. But luckily I got to the injectors before the rust did again. There's still a small hiccup but I'll spend my next free day flushing the whole system and cleaning and checking all of the filters once more to make sure it doesn't get into the injectors again. Thanks guys for all the help. My assumed certainty gets in the way sometimes

 

- Charles

[Indiana]

The rust flows through the fuel system you can't eliminate it, the particles are too small. They collect and bind to the steel parts inside the injector and it will happen with those POS spraying generic injectors too. There's also the corrosion from the steel and aluminum being in contact with each other especially when the damper is removed from the fuel pump and the pressure falls off and fuel drains back. You turn the pump on and that crap flows right through the injector.

 

Just because one injector shows up dirty again on a car that is never driven doesn't mean that 100,000 other injectors are the same and that the same lazy hack that tried to clean one injector now works at the other shops because I've had more injectors cleaned than most have ever seen and I've NEVER had that happen.

[nightwalkerancestery]

Oh I've driven it PLENTY since I got it cleaned. The guy did a FABULOUS job on cleaning them. I checked before and after and it was night and day. It's simply what I have in the car. Aka... constantly dirty fuel tank :/ one of these days I'll get it lined. But until then, thanks for your help everyone!

 

- Charles

[apate]

Glad to hear you figured it out.