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Old 08-27-2002, 12:08 AM   #1
Chav
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Default Hesitation at 2900-3200 with Link 2 and turbo

I can't get rid of the hesitation I have at 2900-3200rpm with the Link 2. It feels like a revlimiter almost until u pass over it. I have the datalog and map if anyone wants to look. The only thing that shows up on the data log when this happens is the voltage drops from 14.0 volts to 13.9 volts. This happens at anything heavier than very light throttle. I can't attach the map or datalog, but if you give me ur e-mail I can send it.

Relevant Mods are:
Link 2 (wired myself)
Ludespeed stage II
SPG mod

-Chav

P.S. Skywalker, you have a pm.
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Old 08-27-2002, 01:59 AM   #2
WRC 555
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check your spark plugs...I'll bet you have to get new ones.

Right now I have a slight hesitation at around 4200RPM. I even had it when my car was N/A with the Link. I know your supposed to run a bit richer and take some timing away from there but that hasnt helped at all.
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Old 08-27-2002, 02:01 AM   #3
Chav
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I just put in the 7 heat range copper NGK's like three weeks ago. I'll try putting in a new set tomorrow, see if that fixes it. They're so cheap it wont hurt to try. Thanks for the suggestion, I'll report back on the situation tomorrow.

-Chav
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Old 08-27-2002, 05:04 PM   #4
Joncas
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7 heat ranges? Thats a huge difference. Wouldn't 2 be more appropriate?
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Old 08-27-2002, 06:13 PM   #5
skywalker
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Actually you should try NGK 6's. They are one step colder which is what you should be using.
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Old 08-27-2002, 06:19 PM   #6
Chav
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I put in the new plugs and checked the old ones. You can easily see that number 3 is running lean when compared to the rest of the plugs. 1,2,4 are identical while 3 has a brownish spot on the electrode while the rest have a black/brown spot. While I was in there I also checked the compression all are within 5psi of 200psi. I also checked the wires which are fine. I then reloaded the link 2 and than loaded the map I've been using while the car was running. The car has the exact same hesitation.

6 heat range NGK's are stock and 7 heat range are one step colder. NGK is weird in that higher numbers indicate a colder plug.

Skywalker, I'm hoping that you have an idea about what's going on because I'm completely stumped. It hesitates the same with no timing throughout the map as well.

-Chav
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Old 08-27-2002, 06:46 PM   #7
8Complex

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7's are fine. I honestly have no suggestion as a solution to the problem. *shrug*
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Old 08-27-2002, 06:48 PM   #8
skywalker
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Oh yeah that's right my bad 7's are the colder step. I always mess that up.
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Old 08-27-2002, 07:00 PM   #9
skywalker
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Your timing looks a little low between 2900-3500 RPM's. Your fuel looks a little high in that area also. Try adjusting those items and let me know how it turns out.

Also PM'ed you some more info.
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Old 08-27-2002, 08:14 PM   #10
Chav
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Fixed!! Skywalker is da MAN!

The entire map was really rich, I went threw and redid the map and it looks much better. What I didn't expect is that between 20% and 80% throttle the same amount of air is flowing threw because of the boost. I was tunning the car like it was still n/a and adding fuel based on throttle. I had to lean out the area with hesitation by 60.

-Chav
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Old 08-27-2002, 09:02 PM   #11
8Complex

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Is the Link TPS based load maps???
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Old 08-27-2002, 09:07 PM   #12
WRC 555
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sweet!

I'm having very minor misfires in vaccuum. It seems to occur between 3000-3500rpm. I was running NGK BKR7E's then fried those when I put in the new injectors, ran too rich initially
Then I put in Denso Iridiums and those seemed to work well but I had a few misfires in vaccum occuring randomly.

I just put in the last new plugs I had which are the BKR6E's and now the misfires are VERY small. The car definitely seems to like running on copper's (thank God---cheaper )

The problem I cant seem to fix is that when in WOT, I get this jerky hesitation at right around 4000-4200RPM. I know I'm supposed to pull back a little timing there and maybe richen it up a little but is there anything else I should do?

I have row settings to MAP. When I put MAP+TPS, the car does not start again when I turn it off. Since I have MAP settings, I also put enrichment to MAP as well.

Any help is appreciated.
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Old 08-27-2002, 09:10 PM   #13
Chav
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8complex, I have it set on map + tps. There are other options such as only map or only tps. Under the map + tps mode it will go by the tps reading to determine fueling and enrichment (when under vacuum), but when there is boost it will go soley by the map reading. In my map it would run fine under vaccuum and then 2900-3500 (when the turbo built boost) it would switch to the appropriate zone and dumb fuel in.

WRC 555, I'm on my way out now, but my car doesnt have the 4000-4200rpm hesitation. When I get back tonite I will tell you what I did to solve it.

-Chav

Last edited by Chav; 08-27-2002 at 09:15 PM.
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Old 08-27-2002, 09:22 PM   #14
skywalker
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WRC 555,

You actually trying to fix a common problem most people have, including myself. You said you are getting hesitation right around 4000-4200.

This is a problem point in the RS especially, even with the damn stock ECU I had this problem except much worse. When you are driving hard, and shift quickley between gears this is where the next gear up usually starts, so you will run lean and possibly ping.

The solution right now is to set the values to where you think they should be for driving normal driving and then lower the timing point about 2 degrees around this area of problem (4000-4500 RPM's, and MAP based on boost levels). Try to keep the fuel consistent around that area if not lowering it a tad.

Last edited by skywalker; 08-27-2002 at 09:30 PM.
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Old 08-27-2002, 09:31 PM   #15
WRC 555
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Yeah I'll keep the fueling the same. I'm running pretty rich right cause when I take out the plugs they are pretty black. Its a 10.5:1 ratio in boost so its not too rich but safe.

I dont really trust our stock knock sensors but after datalogging my knock it really good. It climbs from 5 to around 20 consistently to redline with no big jumps.

The funny thing is at the point of 4000-4500 there in no pinging, its a steady 8-9. So it maybe the cams or something?

I'll try taking out around 2-3 more degrees there and see what happens.

There was a time when it went away, but after the turbo went it came back

We have to figure this out so I can focus on tuning for 10psi

btw skywalker...what spark plugs are you running?

Thanks for your help!

Last edited by WRC 555; 08-27-2002 at 09:36 PM.
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Old 08-27-2002, 09:36 PM   #16
skywalker
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Hmmm, I wouldn't take out anymore timing in your case. It sounds like you are just running to rich, I would try lowering your Master Fuel a little bit, but try keeping your idel around the the same point if it is not to rich. You should be at 11.0:1 - 11.5:1, for optimal use.
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Old 08-27-2002, 09:39 PM   #17
WRC 555
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If I lower the master fuel then I would have to re-tune all over again cause all those numbers in every zone would need to be raised appropriately right?

Let me try leaning it by a few points in that area and see what happens.
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Old 08-27-2002, 11:54 PM   #18
PunKidd
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That's funny. My hesitation went away after I put on my turbo. Just some lucky tuning I guess
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Old 08-28-2002, 03:01 AM   #19
Chav
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Skywalker hit the nail on the head. That is exactly what I did to get rid of the hesitation. It is a combination of pulling a degree or two out of the timing, and leaning the mixture. This worked for me with the turbo, but didnt do much when I was n/a. When I was first n/a with the Link the hesitation was very bad and when I did what Skywalker said the hesitation became more like stock. Jeremy (HndaTch627) said
here that it has to do with the air valves at the tip of the injectors. This and the cam theory are the only two I've heard of that I believe are the possible cause.

-Chav
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Old 09-28-2002, 06:54 PM   #20
Chav
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I'm still stumped about the hesitation. Reducing the fuel worked for the part throttle hesitation, but made the car run lean at WOT. Rerouting the vacuum lines helped reduce the hesitation, but now it is back. I can't figure out what is going on. I do have a few theories though.

Bad Link 2 ecu

Something with the dual feed fuel lines

The stock FPR is too much of a restriction and the fuel pressure goes up so high that the injectors go static and stick closed/open.

Something wrong with my injectors

While driving the other day I noticed that if I'm crusing and driving in the 3000-3500rpm range and give it throttle than let off several times over the hesitation point the car will start to ping. The whole car shudders as I pass over this point. What to do?

I'm thinking about buying a fuel pressure gauge and seeing if my theory of the incredibly high fuel pressure at 3000-3500rpm is correct or just buying an svx fpr. Lately I've been leaning towards a glitch in the Link 2 especially since the data logs show nothing out of the ordinary during the hesitation (except you can see where the rpms don't increase steadily). I'm also doubtful of the dual feed fuel lines or fpr causing the problem because many other people have a similar set-up. Maybe the injectors are to blame, but then the idle would suffer.

The weirdest thing is that when I first put the turbo/link2 on the car it would hesitate at 4500-4600rpm 5100-5300rpm. The hesitation was so rough that it felt like someone ran into the back of the car. Than after playing with the link 2 the hesitation at those points went away and moved to 3300-3500rpm.

-Chav
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Old 09-29-2002, 12:03 AM   #21
Midwayman
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Yo Chav,
If you can post up your PCL and a datalog somewhere, Id be happy to look at it and see if I can see anything.
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Old 09-29-2002, 07:08 AM   #22
xephyr
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Try setting fuel injection mode from "sequential", to "group" firing.

I had the same problem, and it got rid of it.
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Old 09-29-2002, 02:12 PM   #23
PunKidd
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Don't you have to rewire your injectors to only run off of 2 chanels if you do that?
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Old 09-29-2002, 02:28 PM   #24
Midwayman
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Says in the link manual that you should run off channels 7 and 8 to do that. Besides, you car is *supposed* to run sequential.
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Old 09-29-2002, 05:52 PM   #25
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Yes the manual says you are supposed to run just wires 7 and 8 for group fire. However, I was beating my head against the wall with CHav's same problem. I tried group fire mode, and problem was solved.

Remember, the Link fires in group fire method when cranking. The largest benefits to sequential are early in the rev range, and also for emissions.

There are plenty of 500+ HP hot rods that use carburetors instead of sequential fuel distribution, so running in group fire doesn't make me feel so bad.
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