SVT track problems

[Jasper]

First off, hello and thanks for allowing me to participate. I live in Texas, but I grew up in California (Gilroy - garlic anyone) so maybe I can be an honorary member. I wanted to query the collective technical expertise of this group about an issue I am having a tough time sorting out. I have a 2005 superlight with the SVT zetec with upgraded cams from caterham usa. I bought it with 800 miles on it and now has around 6500. I replaced the alternator soon after I got the car but have no other major issues. I have had the car for about 2 years. I tracked it for a weekend event soon after I got it with no problem. Since then I have intermittent problems on the track. It drives fine on the street, and I even drove it round trip from Dallas to Aspen for LOG a couple years ago. Here is the issue - on the track at unpredictable times, but often in corners, the car will almost stall - the speedometer and tachometer immediately go to zero and the engine almost dies and I obviously slow way down, but then just before it dies I can give it some gas and it fires back up and seems to drive fine. I can't reproduce it on the street. It is unrelated to the volume of gas in the tank and I have bypassed the inertia switch with no benefit. The behaviour of the tach and speedometer make me believe its electrical in nature. I have access to a dealer/service center (British Auto in Fort worth) that have a lot of experience with the cars and service many locally raced cars and they couldn't find anything obvious. I would like to get the car back on the track, so I was wondering if anyone had some ideas of where to begin. I know these issues can be difficult. On a different note, I'm planning a summer drive in the car from Texas through northern arizona into california this summer, so if anything is going on let me know. Thanks in advance.

[magnusfeuer]

Jasper,

Welcome to CCC. We have extremely lax membership rules (and morals). If you sign up, you are a member.

I had a similar issue like you a couple of years ago and it turned out to be a loose relay in the fuse box.

In your case the loss of power has to be very close to the battery since you lose both tacho, which is fed by the ECU, and the speedo, which is fed by the chassis harness.

First of all, check that your battery terminals are tight and snug. Shake the cables with the engine idling to see if the terminals or the crimping are giving out.

If that doesn't trigger the fault, try to shake the fusebox and jiggle the individual relays in the box when the engine is idling. I had to remove the ignition relay and bend the little metal tabs that make contact with the relay pins to make it sit more snuggly. Just to be on the safe side, I tie wrapped all the relays down to the relay box itself. Haven't had a problem since then on or off track.



/Magnus F

[Jasper]

Magnus F -

Thanks, this is exactly the info I was looking for. I tried the battery terminals and they seemed fine, but this bit about the tach and the ecu and the speedo and the chassis harness, I could monkey around in my garage for a week and I wouldn't be any closer to knowing this. I'll give this a try when (if) I get home and follow up.

Cheers,
David

[Doug Liedblad]

Jasper

I had a similar problem as well. Drove me crazy as it would work fine for months then suddenly cause the car to quit. Anywhere from 30 seconds to 3 hours later the car would start again. Wiggling wires never found it.

The wire that feeds power to the ECU comes out of the chassis wiring harness separate from all the rest. On my car it's a 10 or 12 gauge green wire with an insulated spade connector. Find the big chassis to engine loom connector and trace it back towards the firewall or where it comes out of the transmission tunnel. The lone green wire is it.

I traced my problem to the mating connector from the engine loom. It was crimped over the insulation of the engine loom power wire instead of directly to a stripped end of bare copper. It obviously made some contact as the engine would run. The crimp went thru the insulation in a couple of spots but it could not have been very good even when working. You may have to remove some of the wiring harness covering tape or heat shrink tubing to see the connector.

Again the problem was with the connector on the engine loom made for the Zetec engine. Not the connector from the chassis wiring harness.

This was on my stock Zetec from a Contour running the stock ECU. I believe the wiring harness was made by Caterham USA but don't really know for sure.

I've since switched to the SVT Engine and Pectel T6. I made my own engine wiring harness.

Doug

[Jasper]

Doug -

Thanks, I'll check this as well. As an aside - whats the benefit of the Pectal T6 ecu?

Once again, I appreciate the input.

[magnusfeuer]

The Pectel T6 is a full on race ECU where you can configure the injectors, ignition and a myriad of other things with to a very high level of detail. Configuration is done using a laptop. You can also do data logging with it, although the data log analysis software does suck pretty royally.

The T6 is the bigger version that Doug and I have, that was also used in the Atlantic Kart Series engines. It has launch control, throttle blipping and a ton of other stuff that no one is using.

The T2 is a smaller version focusing on 4 cylinder engines and with some of the higher end stuff from the T6 omitted . It uses the same configuration and data logging software.

Both these systems are quite aged, although very reliable (even if Doug has had issues with his unit). You need a wiring harness to connect it to your car, as well as a mapping session on a dyno. However, if you run a fairly standard SVT, you should be able to find a Pectel map for it out there.

We tend to use Pectel since we know them inside out. Other brands to look for are Motec and Emerald.

Disclaimer: I know the previous distributor of Pectel who sold almost all the units on the market today, and run a separate company with him.

/Magnus F.

[Jasper]

You guys are good. I think I'll try to get my car running correctly first.

[Doug Liedblad]

Jasper

I'm assuming you are using the stock SVT ECU. This should be all you need.

I wanted to do more than you can do with a stock ECU, since then Pi has come up with piggyback units for the T2.

This wasn't even on the drawing board when I started, plus it cost a lot more than what I spent to get the T6 and build my wiring harness.

Doug

[mopho]

Davids car is pretty much the twin of mine, minus some details and the individual throttle bodies.
Magnus and Doug have become very well aquatinted with my car