Stalling and poorly running Duratec

[jlumba81]

I don't suppose there's another tps you can use that has the correct voltage range?

[frizille]

I don't suppose there's another tps you can use that has the correct voltage range?

 

I tried 2 different ones as I already had a spare on the shelf. Both read the same voltage so it's a fitment issue with this throttle body. It's like the butterfly valve, spring, and bracket are just a tiny bit off.

[frizille]

Reading this thread is like reading an Agatha Christie novel: lots of suspects, false clues, red herrings, and occasional small break-throughs. I "tune in" every day to see if the suspect has finally been caught:)!

 

LOL - great analogy, although I was always a Hardy Boys type of guy myself.

[frizille]

Finally some good news! Davestruve came over on Saturday afternoon for a bit and helped try a few things and confirmed a couple other things were ok that I was worried about.

 

 

1) The smoke coming from the exhaust isn't coolant, which is what I was *REALLY* worried about. Instead, we arrived at the conclusion that it was just a lot of moisture burning off and the extra fuel in the exhaust burning off from my FUBAR'd attempt at changing the spark plugs several weeks ago.

 

 

2) We got the idle tuned using the idle screw on the throttle body to something healthy, it was around 1000rpm, and with the TPS slightly offset from its mounting holes and showing .42V / throttle site 0.0 we were able to get the car running up to temp and the radiator fans kicked on at 98C just like they should. The car seemed to be running great and where I used to see the idle at ~1600 RPM and pulse +/- ~500 RPM it was now idling right at 1000 RPM +/- 30 RPM. Significantly different engine behavior!

 

 

3) The voltage we saw in Easimap was around 12-13V, but didn't see the alternator kicking it up to 14V as we would expect. Dave had an issue with his 7's alternator not running due to a "wiring fault" and it exhibited similar characteristics. I'm going to pull the alternator later this week and run it up to Autozone or Pep Boys for them to test it.

 

 

4) I sent Caterham an email over the weekend explaining the issue with the TPS and that the alignment of the butterfly valve and TPS mounting holes makes it mechanically impossible to hit ~.42V. To do so, I have to remove the idle screw entirely from the throttle body and thus completely close the butterfly valve, but that's an intractable solution as the car needs air to even start/idle. With the throttle cable bracket literally on the throttle body stop the butterfly is completely 100% closed and the car won't start. Dave and I tried that - the car has to have some air to run. Caterham's reply was to adjust the idle screw until the TPS reads .42V. I just shook my head and tried to explain it again, that the idle screw is completely removed and the butterfly / throttle body can't mechanically close anymore than it is and it still won't read a low enough voltage.

 

 

5) Going from someone else's comment that you need to set the min and max TPS voltage in the ECU, I suggested to Caterham that I send them the ECU to reprogram with the right value of 1.20V instead of .42V cause I can't get it that low through aligning the TPS with the throttle body. They replied again that I had to adjust the idle screw... /face palm.

 

 

6) With that dialog in mind, I made a video tonight of exactly what it's doing. You can see it at:

 

 

7) I feel as though this would be a simple exercise to fix *IF* I could access the ECU. But the MBE 992 that comes with the car from Caterham is locked. So I ordered a new MBE 9A4b ECU from SBD Motorsports this morning. I sent them all the specs for what's on the engine, it's pretty much just a stock 175-180hp setup from Caterham, and they said they will load a base map that should work pretty well. I can tune remotely with them as necessary. I also was tempted to order a set of ITBs with it - in for a penny, in for a pound - but since I've got an S3 chassis would have to cut the bonnet and that's more trouble than I want to undertake right now. But all in good time...

 

 

So, anyway, that's where I'm at. I'm covered up with work this week and don't expect I'll have any time to get the alternator off until maybe Friday night, but I'm gone this weekend so early next week will be the next opportunity to get some progress made. That may work out ok though, the 9A4 should be here Monday/Tuesday next week so can put that in before messing with the alternator and rule one thing out at a time.

 

 

Dan

[Dave W]

Dan

I had a problem with a 4AGE TPS, not aligned correctly. My solution was to remove the TPS and pull the tab bracket that engages the TPS, off the TB shaft. It was postioned by two locating flats on the shaft. I just filed the flats about a .04" [in opposite cross corners] allowing it to rotate slightly. Then re-attach the shaft nut while hold the tab bracket in the new location. Dave W

[Off Road SHO]

Dan,

 

So your engine doesn't have an IAC valve? Idle air control or bypass?

 

Tom

[frizille]

Dan,

 

So your engine doesn't have an IAC valve? Idle air control or bypass?

 

Tom

 

Nope, just a single butterfly.

[frizille]

Well... I wish I had better news as the weather is wonderful out. Partly cloudy and 80 degrees with not too much humidity. Sadly, the car is still FUBAR.

 

This past week the new 9A4b ECU from SBD Motorsports showed up with a barometric sensor. I got the ECU swapped this morning but something isn't right. The TPS and throttle site are inverted in the programming it looks like; the TPS reads 1.08V which is correct (I checked that on the stock 992 ECU this morning before the swap) but the throttle site is 13.5. When I move the throttle to full open, the voltage on the TPS goes up as it should from 1.08V to 4.5V but the throttle site goes DOWN to 0.0. It should be the other way around, when TPS voltage goes up, throttle site goes up. I've been poking around in the Easimap software for close to an hour and can't for the life of me figure out how to correct it. So... I'm stuck until I find an answer or Monday gets here and I can ask SBD.

 

Second challenge is the barometric sensor wiring. I've got the pin out from the instruction sheet they gave me, but the pin 4 I'm supposed to use on the PCM/ECU connector is occupied by the GY (green yellow) wire. Not sure if I'm supposed to tie into that one, move it elsewhere, or what. They didn't send me any new pins either so if I'm supposed to cut and splice I have no way to do it. More questions for SBD.

 

Also, a new lambda sensor and TPS sensor showed up from Caterham. Based on the stamp date it looks like it's been floating around the post office for 2 weeks. Neither of those items are necessary - mine are both working fine - so put them on the shelf.

 

Now that I've got the old 992 ECU out of the car that's going back to Caterham for diagnostics and reprogramming.

 

Dan

[frizille]

I'm overdue for an update so here goes...

 

- I fixed the TPS direction. From SBD: Most of the Caterham/Cosworth throttle pots were wired backwards, so MBE created a piece of software to save all the cars from being rewired. Your throttle pot sounds as if it has been wired correctly. It is a simple case of reversing the throttle pot direction in the software, please ensure you are on the Advanced level, this is done by clicking on the bottom right corner of the screen, a box will then appear and select Advanced. For those that come after me, the navigation to make the fix is: In Advanced mode, you want to go to the System Menu (at the top) > "Maps and Settings" > In the Maps and Settings window go to "Throttle Position" > "Throttle Position Limits and Default Setup" > "TPS 1 Direction" and change it to read "Clockwise Throttle Pot" (or anticlockwise if your wiring is the backwards way).

 

- I didn't hook up the baro sensor yet, but the wiring order is red wire to the +5V reference pin which is either pin 4 or pin 22 in the Caterham harness/PCM. I will have to splice the wire into the existing pin though which makes me a bit nervous. From SBD: "Your new MBE9A4 would be looking for the barometric pressure sensor, but if it is not fitted it will simply detect it as a fault and assume its default reading of 1000 millibars, which is the pressure at sea level. This will not effect how the ECU runs, the only time you would get a problem is if you attempt to map your engine at a different altitude and therefore the pressure would be different. The quick short term fix would then be to change the default to a pressure seen when mapping is carried out." So in lieu of wiring it, I just set the baro default to 1.020 bar which was the barometric pressure in Atlanta today according to the Weather Channel website.

 

- I bumped the Throttle Index Map up from 1.05V at site 0 to 1.15V at site 0, adjusting all the sites at once (Control+A, PgUP) so really just shifting everything up .10V. That made the throttle site at 0 for my throttle body with a TPS value of 1.12V and 1,000 RPM idle.

 

Once I did all those things I hit the button and it started! Success... but only partial. It's running a bit lumpy and any application of throttle makes it want to stall. I also noticed the ignition timing was pegged at 40 degrees at idle which seemed really high, however, understanding ECU mapping is brand new to me and from reading supposedly you want a high ignition advance at start / idle for fuel economy and to prevent kick back. That still seems very high though.

 

I have no idea where to go from here so will have to do a bit of learning. I can see the fuel and ignition timing maps and I'm exploring Easimap to get an understanding of how each map relates to the others. I also put a post up on Blatchat to see if anyone with an R300 (~175hp) has a map they can share for the 9A4 ECU. If so, that might save me some time or at least give me a reference in comparison to mine.

 

The Caterham 992 ECU is also enroute to the UK. It was $148 via UPS and only $37 via the Postal Service... so it's on the slow boat. I'm hoping to get it back in a couple weeks.

[yellowss7]

I had Steve at SDB do a remote tune on my car this spring. I took the car to a performance shop that had a dyno and good wireless signal and Steve mapped my car from England. So it is an option for you if you need it. Tom

[frizille]

I had Steve at SDB do a remote tune on my car this spring. I took the car to a performance shop that had a dyno and good wireless signal and Steve mapped my car from England. So it is an option for you if you need it. Tom

 

Just traded emails with Steve; going to try to get a tuning session on Friday with him. Thanks for the idea!

[yellowss7]

Say hi to him for me. I'm very happy with the results of the tune. Car is running great. Good luck. BTW, I used the app What's App to talk with him on the phone. Free call if done on wifi. Worked great. Tom

[frizille]

VICTORY!!! I spent an hour with Steve this morning (he says hi Tom) and we've got the motor ticking along nicely at idle. Steve was incredibly nice and helpful. I was pretty close with the tuning I had before, but now I understand more about what the motor is doing and how the different settings all relate to each other. We bumped up the TPS voltage to 1.17V, and thereby opened the butterfly valve in the throttle body slightly more, to get the lambda to .90 at idle. We tuned the throttle index map up slightly to account for the higher voltage coming from the TPS and let it warm up. It runs great! Prior to the new ECU, when using the old Caterham 992 ECU, I'd get a huge dip in RPM when letting off the throttle and the motor would be close to a stall. None of those issues with the 9A4 and Steve's map.

 

Next steps are to drive it this weekend and see how it runs at moderate RPMs. I'll get a rolling road session scheduled in the next couple weeks. Steve also suggested looking at the Innovate LC1 system to get a bit better data with a wideband vs narrowband O2. He's going to send me a 2nd map with that enabled and the wiring PIN out I'll need to use. I've still got to hook up the baro sensor so will just do both at the same time. Having control of the ECU is SOOOO MUCH BETTER than being limited by the locked ECU from Caterham. I'd defintiely recommend any new owners dump the 992 and go to the 9A4 as part of the initial build - the results are really night and day.

 

I see a light at the end of the tunnel finally!

 

Dan