Golf IV / Jetta IV :: Losing Power And Boost At 4k RPMs After Tune
Jun 16, 2015
I have a 2002 gti with an apt software tune...
Whenever I'm on the interstate in 5th gear for a while. And I'll start to speed up. Once 4k kicks in. My boost no longer works when it normally pushes like 22psi
Then after slowing down. No matter what gear I'm in. It limits back to 10psi of boost and once I hit 4k. It goes super slowe and boost won't work
The guy told me that I should get a smoke test done (idk where or how to do that)for my vacuum lines and that I have a cylinder 4 misfire. It may be a bad coil or spark plug. But I'd like to get some performance out of my car and I don't know what else or where to start. I am new to this.
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I have a 2002 gti with an apt software tune. Whenever I'm on the interstate in 5th gear for a while. And I'll start to speed up. Once 4k kicks in. My boost no longer works when it normally pushes like 22psi. Then after slowing down. No matter what gear I'm in. It limits back to 10psi of boost and once I hit 4k. It goes super slow and boost won't work. I'm not sure what else I should get to restore my car to perform fully.
I'm currently on the factory ko3 turbo and the previous owner had nitrous hookups and lines to the motor.
I'm already 3k into fixing it. Needed new shift cables and a fresh transmission
I'm hoping to push about 250hp maybe 300hp
The boost problem is fixed once I turn the car off and back on. I just want it to work again without having to spend an arm and leg on parts and labor. My mechanic works at Volkswagen dealership. But isn't allowed to work on my car due to dealership policies about working on vehicles older than 10 years old. The guy who tuned my car professionally at an apr shop told me that I should get a smoke test done (idk where or how to do that) for my vacuum lines and that I have a cylinder 4 misfire. It may be a bad coil or spark plug. But I'd like to get some performance out of my car and I don't know what else or where to start.
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2003 jetta gls 1.8t 5spd - gts stage 1 tune(gonzo stage 2)
tt 2-1/2" downpipe with high flow cat
turbo smart splitter valve(set to divert only)
turbo inlet pipe
homemade intake with k&n filter
stock n75 valve (f)
So in first through 3rd gear my car gets 20psi of boost then at 3,500 ish rpm smoothly starts to lower down to 15psi. but in forth and 5th gear the boost drops faster, enough so the diverter valve actually opens. then the boost will bounce up and down, around 15psi. the car still accelerates but with obvious power loss.
Is my diverter valve not "firm" enough? it is adjustable, so I've tightened it as much as it can. it doesn't seem to change anything. it came with spring spacers to make it tighter, but I haven't tried that yet.
Is it something with the tune? not enough fuel, need bigger injectors? The problem is only at about 100mph, so its not a big deal. I would like to get it straightened out if possible.
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I have a 3inch cat back exhaust, cold air intake, and a stage 1 apr tune. I just installed a front mount intercooler. When I spool my turbo in 1st gear the car loses all power at 4 grand and just bogs out after that. Rpms keep climbing but the speed doesn't move. What's going on?!
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I have been looking around for some boost information. I have come across a few threads that have boost graphs, but the images are no longer available. I have tried to get a hold of some of the posters, but no luck.
I only recently hooked up a boost gauge and have been monitoring my boost more. I had a slight feeling before I hooked it up that I was losing a little boost at higher rpms. Between 4500-5000 my boost drops from 18 to 15 and then from 5000-6000 it drops to about 10. I know it's sometimes normal for boost to drop at top end, but I'm not quite certain it's supposed to be that much.
I installed the Spulen Boost Pipe Kit hoping it may make some type of difference, but it's the same. What it might be? I have checked all my pipes as best as possible, but couldn't find anything.
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I have a golf mk4 1.8T AGU, about one week after i had my k04-023 turbo on and all the Stuff that comes along it started "stall" (don't know if its the right word??) in the High gears, most 5th gear but it first start doing it when i hit boost (3000rpm)
I runs on Stock n75 valve.. I though i could be a boost problem, maybe the Stock system cant handle it? I did install a boost gauge to see if it was the was the problem, and it dont Seem like it. In first it runs from 1.4 bar and drops to 1.2. Same in second and third. But in 4 and 5th it goes to 1.7 bar and drops to 1.4.. I did wonder it maybe the n75 valve cant handle 1.7 bar??
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I bought a ts 6 position from kt performance with PHP canned tunes pretty much and on the 140 tune I get no black smoke under throttle, now I would imagine this is normal with stock injectors because im sure the turbo can keep up somewhat. But the problem is I only make 16 psi max so shouldn't I be dumping black smoke? I know the low boost is because I have a hole in the intercooler pipe next to the power steering pump, but do I have low fuel pressure? I would imagine with only 16psi all the fuel will not be burnt. Hpop can hit 2800 and hold 2500. But ipr hit 80% under full throttle at 3k rpm and had trouble shifting but other than that never sees over 45%. I want to know whats going on with the fuel not boost, just to clear things up. And I don't really feel any power loss im stock. 99 f350 7.3 4x4 long bed cc
And just to be clear I am NOT trying to Roll Coal but a nice smoke trail when flooring it past people who cut you off would be nice
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So I installed a new f23 turbo about a month ago now. Doug over at frankenturbo has been working with me to tune my car, but we have figured there is a possible boost leak. I've checked all my hoses and can not find any bad connections. My current setup is a forge twintercooler, cts intake, and a ecs boost gauge. I've been over everything 3 times now and can not see where anything could be leaking. I can tell you when in low rpm's the power and boost is very weak. Doug suggested to turn the wastegate up and we did. Still no result for the low rpm to build boost. I'm at a loss.
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car is losing boost as soon as it goes above the 3500 range.
it will reach peak boost at WOT but begin to tamper off as it goes higher in the range and will reach as low as 5lbs towards 5-6k
i have an apr stage 2+ tune and my peak boost is usually 17-19 lbs.
check all hoses and everything checks out fine.
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I've had the car for almost 5k miles, no issues. Only performance part on the car is a USP 3" catless down pipe with an O2 spacer. Car performed fine with it. Today I got an APR stage 1 93 octane tune. A few hours into the tune on my way home from work, I went to change lanes and the car hit some type of a wall with the RPMs. At around 3200 RPMs, the car felt like it went into limp mode. Did not let me pass 3200 RPMs. I got off the highway and had to keep the RPMs up because the car died at lights. Pulled into my driveway, plugged in my VCDS and there are absolutely no codes coming up. Nothing. But starting the car the car cranks and I have to give it gas for it I barely start.
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I have a 99 Jetta MK4 2.0L. I purchased it last month and have been having issues since.
First it was the coilpack that made my engine bog.. (at the time, my transmission was also clunking into gear, getting stuck in gears etc.) changed coilpack and it went away.
Then I had issues where the car would turn, but not start. Changed the Crankshaft Position sensor.
All was good again, then my transmission started to do the clunking (but no getting stuck in gear) and then i started losing power during takeoff.
Then it got really bad, I got home and tried to start it up again, i can floor it on the gas and the car will studder and bog out for a good 3 seconds, and then slowly accelerate into gear.
Some points i was in neutral trying to rev and it was bogging then also.
Btw, coilpacks were changed, all o2 sensors were changed, and the spark plugs have been done recently. Pulled codes,
- P0422 Main catalyst efficiency below threshold
- P0103 Mass or volume air flow circuit high input
- P1127 Long term fuel trim be system too rich
- P0715 Turbine/input shift speed sensor circuit
Also tested driving again, bogged out initially then started to move. Checked if i could get past 40km/hr and i hit 60km/h. After driving a little bit it seemed to be a little bit more responsive, but still boggy.
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I have a 2005 Volkswagen GTI with 80k miles. Just yesterday I went to school and the car drove fine. But when I came back and tried to start my car, it stalled out after a few seconds. Now I thought this was a bad fuel pump until I checked it and found that the fuel pump wasn't receiving any power. I checked the fuse and it was intact. So then I went to check the relay and found that if I unplug the relay and plug it back in, the fuel pump momentarily receives power for about 2 seconds then nothing. Any clue what the interference could be?
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I have a 02 Jetta TDI with 186k miles. Couple weeks ago it all of a sudden started making boost noise when I was driving to work and then on the way back I was getting almost no power. Like over boost and under boost issue, so I assumed it was the MAP sensor. I got busy next couple weeks and then tried to start the car but now the car is not starting.
Completely charged the battery so its not the battery. Looked online and it seemed like it could be the 109 relay for the fuel pump. I pulled the back seat off and I can't hear the fuel pump prime up. I got a new relay from auto zone and put it in, still same thing. I don't want to have to replace the fuel pump only to find out its not the fuel pump. I ran the code and I'm getting the P1556 code (charge pressure control negative deviation).
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I did a tune up on my 20th last week, plugs and coil packs and oil change. now i have a strange idle that it wasn't doing before. i checked all the plugs over again and they are gapped fine and i have no CE light on. Every now and then my RPM meter will jump down and then right back up, same with the boost meter at the same time. i had it looked at at the garage i go to and they said they cant seem to find anything wrong. What might be causing the rough idle? keep in mind this only started happening RIGHT after the tune up.
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I'm currently moving cross-country from LA to St. Louis. Had routine maintenance done b4 I left. I've only made it to New Mexico so far b/c my car is losing power after logging 250 mi. RPM's also become erratic. Doesn't completely stall, but won't let me go more than 45mi/h. After a rest break, the problem doesn't re-create.
At my first mechanic stop, the computer checked-out as ok. That mechanic changed the spark plugs and also told me the 2004 has no fuel filter (fuel filter being my suspicion of what was wrong).
Today it lost power again. Jim Bob at a rural garage said maybe the alternator or fuel pump. I have an appt. at Pep Boys tomorrow, as the dealers don't have any avail appts. until Fri.
The contents of my apt. are in the trunk and backseat. Is it worth it to remove them (to get to the fuel pump) at the cost of another hotel day, or should I limp home at 250 mi. a stretch?
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The past couple days when driving to school in the morning i've been noticing that my car starts to rattle and struggles to accelerate once I pull out of my driveway. Once i get to the next stop sign to take off the car runs fine like nothing ever happened. My check engine light doesn't come on though. I usually let the car sit for about 30 seconds to a minute before i start to move the car. Mods I have are Unitronic stage 2, Forge 007p DV with yellow spring, and 3" downpipe.
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Our ABS light, anti-skid light, and engine light are on. The light came on when 3 year old son hit it. It just never went off. Dealership hooked it up to diagnostics and said we needed to spend almost 500 on a new ABS system. ALSO, at the same time, the car now sounds like its working very hard to accelerate. The rpm's go up, but there is no additional power. Is this connected to the ABS problem, or is this a transmission problem? Took it to a mechanic and he didn't check the transmission. After talking to him, he said it could be the transmission.
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I own a 2001 Jetta GLX 12v VR6, lately the car has not been running well. It chokes the power past 3500 rpm's and will continue running poorly and sound sort of like a Subaru boxer engine. Sometimes it corrects itself and runs okay but goes back and forth.
I ran the codes on VAG COM:
6 faults found:
17551 - Load calculation cross check
P1143 - 35 - 10 upper limit exceeded - intermittent
16712 - Knock Sensor 1 (g61)
P0328 - 35 - 10 Signal too high - intermittent
[Code] .....
I ran VAG COM a couple of days before these codes came up and I had a different code dealing with air/fuel mixture, something about fuel running to rich. I'm stumped.
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I understand how the waste gate is supposed to work at high rpms / boost.
I believe that as long as I keep the max boost down, that I can run with the waste gate plugged in order to goose the power a little in the 2000-28000 RPM range. Since the truck is stock and there's no intention of running higher RPMs, it seems like plugging the waste gate is a good idea. I just want to make sure that I'm not missing something.
It appears that the wast gate also opens when at idle and possibly when you let off the throttle. Are these important functions of the waste gate as well?
Here's a chart showing waste gate operation...
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my car into VAG COM and since then it hasn't boosted past 4 lbs. it has Revo stg 2, K04, aftermarket side mount, full exhaust and a couple other bolt ons. Before the car was spiking at around 23/24 lbs. after pressure testing the system I found that the turbo inlet pipe was lose, so I tightened it. Still no change. I tried holding the battery terminals together for 10 minutes to reset the ecu and I also tried clearing the codes through a handheld code reader. No codes even come up anyways for this. The car is a 1.8T.
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Out of the blue, months ago, the A/C quit working. I rarely used it prior so I can't say for sure if it was losing "coolness." It may have been. And other than hearing a slight hum or whine after turning the compressor off, which it has done since almost new everything was fine. Although it did, recently, before the A/C died, begin to overheat while waiting in traffic. Never did it again.
I have not done a bunch of troubleshooting other than adding some refrigerant and monitoring the fans and A/C clutch to see if they cycled, which they did not (assuming I was reading the fan process accurately). The gauge did read low, I filled it to the green zone, the compressor clutch engaged, level dropped, I added, it cycled, then dropped, all the while still blowing hot air. I quit doing that but it remained on the low side of green.
The car has 180k miles and runs great. I'm getting ready to sell her after 11 years but really need the A/C working to get anything out of it in the South.
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