While playing with my MicroSquirt kits I found that the stock CHT has a quite frequent failure rate. I used a stock unit on the motor I installed and on my trip to Portland I realized it was giving lots of erroneous readings. When I got back I installed another one, and it was fine for awhile, but eventually started giving the same erroneous readings. I found a modern electronic component which replicates the stock resistance/temp curve of the CHT sensor and isn't prone to vibration/heat damage like the stock unit (including new replacements). I would like to find someone who drives their car enough to notice if there is a difference.

Who's got stock D-Jet installed on their system, drives somewhat regularly and is willing to do some testing?

Not in the snow But Cool!

I.ll help.

For once, this isn't me...

I may be able to help. 72, 1.7L with stock D-Jet. I just installed the MPS repair/tuning kit and haven't had a chance to "dial it in," but it's still running ok and I could do some before/after stuff. My CHT was replaced about a year ago and I put one of Brad's spacers on it earlier this year.

What are we trying to fix? CHT behavior or just find a better replacement?

Sweet PM sent so I know where to ship it.

Me?

I have a '76 2.0L (weren't they all that year?) DJet that is a DD. Has nearly 30K on my rebuild.

Send me a PM

I have a 73 and a 74 if you need more help.


Shoe

I run djet and at the present time is my only transportation, so it gets driven everyday. I too have noticed a large failure rate of chts in the last few years. Would love to see an alternative. Be more the glad to help out with this

If you are willing to use an L-Jet system, I can put one on Betty's car. It definitely gets driven all the time.

Cool, four testers should be sufficient to know if it's a good upgrade.

Thanks guys!

Mark can you elaborate?
Were these variances something you noticed looking at a map or glitches in drivability that led you to the CHT & observe issues with their resistance/temp curve?

Mark,
You can send one my way if you want one more data point. My car gets about 150 to 200 miles a week added on the odometer.
Marty

Since I'm running MicroSquirt I can graph the readings. I was getting a bit of bucking, each time the reading jumped it would squirt a bunch of fuel. The first one stopped reading all together and just had high resistance, so the engine always thought it was cold. Thankfully I had my laptop with me so I just turned off the cold-start enrichment and ignored the sensor. The second failure was similar, but never got to the worst case scenario. It would buck occasionally - just a quick miss and then back to normal.

I've observed this with newer sensors as well.. The old ones seem to hold up much longer and to be much more stable.

WHAT?!?!? You mean chasing the TPS and vacuum leaks isn't the only thing that might be causing my D-jet to experience the mysterious buck n hesitate during the normal driving commute?

Very interested in seeing the outcome here. Been upgrading bits in the engine bay to help make my 914 a more reliable commuter

Something else I noted with the stock CHT is the resolution is very notchy.. It may be unresponsive for 20-40 degrees of engine temperature differential, then all of a sudden it'll change. This makes it very difficult to build a MAP of engine temp values in regard to enrichment.