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TGP runs ok, but lacking power


Heartbeat1991

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I have a 1990 TGP I bought in 10/2013. I have not driven it much yet. I've been fixing little things here and there. It runs decent. Kind of. It seems to idle ok, and driving it normal it does ok, but if I step on it at all, it seems to choke out, hesitates. The power is no where near what it should be. I don't know a ton of the car's history. I changed the plugs and wires, with some improvement, but not much. I swapped the crossover, again with some improvement, but not a lot. I just checked my injectors this morning, they are all showing around 12 ohms. I'm not sure what to check next. I have no codes at all. I am thinking about changing the PCV while it's apart, and while the O2 sensor looks newer, I'll change that too. I changed the TPS when I got it. The PO had just put a new one on, but snapped one of the screws off it. So I replaced the entire throttle body. Any suggestions?

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What does a scantool show? Any codes? Any unusual live data, when it's running? Is the check engine light on?

 

You've done a good bit, but without solid data, it's kind of a guessing game as to what's wrong.

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I don't have a scanner that will get live data from an OBD I. No check engine light, no codes. I may check the coils, but I am thinking that's a waste of time. Coils generally work, or don't.

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Update :[TABLE=class: forumline, width: 99%]

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[TD=colspan: 2]what do you make of this :

I put a fuel pressure gauge on the rail. It read 0. I turned the key on, it shot up to about 42, and quickly fell back down. Back to 0 in less than a minute. I swapped the FPR with another spare I had a couple months ago. No fuel in the FPR vacuum line. Leaky injector? It seems to be burning quite rich to me. So that might make some sense.[/TD]

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The EGR pipe was busted off until a couple weeks ago when I replaced the crossover and EGR pipe. It ran about the same. Aside from that, taking off the EGR on a TGP will make it run crappy anyway. It messes with the O2 readings, and fattens it up way too much. It also reduces pressure to the turbo, reducing spool.

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I know this is apples/oranges, but your drivability issue reminds me of a scenario I experienced a couple of weeks ago.

 

I was driving a huge '97 Ford F450 bucket truck with unknown issues. Would randomly stall, and not start up. The mechanic asked us to drive it around, and try to duplicate the problem.

 

In my tinkering, I found that the truck ran just fine during normal driving, but ran like a fucking dog when you tried get any real power out of it. As an experiment, while I was running at WOT on an open stretch of road, I flipped the fuel switch from the front tank to the rear tank. BOOM. Instant power. Front fuel pump was weak under load.

 

I'm wondering if this might not be your issue.

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I was thinking I need to check the rest of the vacuum. Seems like it could also be boost leak somewhere. The fuel pump was new right before I bought the car. I need to find the receipt and make sure it's the right one. But fuel pressure seems to be ok. I'll look into these things. Thanks for the ideas.

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I was thinking I need to check the rest of the vacuum. Seems like it could also be boost leak somewhere. The fuel pump was new right before I bought the car. I need to find the receipt and make sure it's the right one. But fuel pressure seems to be ok. I'll look into these things. Thanks for the ideas.

 

Pressure isn't the only thing the pump needs to supply, it needs to also supply ample volume.

 

 

What intake are you using on the car?

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Pressure isn't the only thing the pump needs to supply, it needs to also supply ample volume.

 

 

What intake are you using on the car?

 

It's 100% Stock.

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It's 100% Stock.

 

Do you have a cone filter laying around? The stock intake hose from the airbox is known for getting partially sucked closed under boost limiting airflow to the engine. Might not be the case with your car, but it's something easy to rule out.

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I don't have one, but it's on the list. It runs quite rich at idle. There is a certain miss in there somewhere. I just have to figure it out. I haven't had time to work on it the past few days. Accumulator came today. Ordered it Wednesday afternoon, it was here by noon today. I was impressed. Snowstorm and everything. I'll likely try to get that on tomorrow.

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Quick update : I swapped the entire coil/ICM assembly today with one of my spares. I think that solved most of the problems. It seems to run a lot smoother, and the few hundred feet I moved it, it seems to have much more power. I will take it around the block later on. But now I think I can concentrate on some of it's other mostly cosmetic issues.

 

Also have more work to do on the brakes. I installed the new accumulator. I did a system bleed. I think there is still air trapped in there. I will have to bleed it again. I no longer have any dash lights ( brake or ABS ), but the pedal isn't feeling right yet. The pump runs about 10 seconds when I turn the key on.

Edited by Heartbeat1991
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that's the way to do it. swap it out and look for any change over time. If it comes back there is many things to try with that ruled out.

 

I am going through troubleshooting with my new wideband and it's frustrating guessing on why it has bad days sometimes. I think it takes it longer to warm up in the winter. I bumped up the idle in my tune yesterday from the stock 775 to 900 rpm's to give the alt a boost. I already had the throttle follower table swept up to a much more drivable level. I did that 2 years ago. 900 seems like a much better idle speed, but as soon as I tried that, the brake light flashed and the anti-lock light stuck on. I think it needs bled again. that usually helps to bleed it often. sometimes it will linger for a few days after bleeding and then go away.

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Did you do the jamming on the brake pedal method? I changed my accumulator last spring and it didn't require any physical bleeding

 

I'm not familiar with that method. My pump sucked the stinking fluid out of the reservoir faster than I could fill it back up. So I'm sure there's air somewhere. Something isn't right. I had a hard time getting fluid from the rears when I bled, and I got nothing from the master itself when I bled that. I need to pull the bleeders out and clean or replace them. I assume there is clogs.

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