timing jumping?

[Trigger]

ok I got all my codes fixed now i am getting code 55 which means all is good but I was wondering why after a little running the engine would rev up really high (2000rpm's) for a little while then go back down so I put the timing light on it to see if it was jumping timing and sure enough the timing was jumping up over 20 degree's and would ru a minute then back to 15 degree's. So the ECU is showing no bad codes so im not sure what it could be I checked all intake for leaks and found none. vacuum seems to be good but does back a tendency to drop but i havent been able to find any leaks. I am thinking maf or cas any ideas guys...Dee anything?

Tim

[dattodude]

Temp Sensor is above thermostat. Sounds a bit unbelievable, disconnect it to see what it happens to your timing.

If it's faulty, it can cause problems with timing.

Chris.

[Not_a_sr]

check your mechanical timming by putting the crank on 0deg BTDC then make sure your cam marks align with the cover behind the cams, you will have to take off the top cover and CAS. when that checks out fine, check the little tooth on the exhaust cam that the CAS runs on , its possible its worn out. then check the CAS with a known good one. also when setting timming make sure the car is at full operating temp. i have had to chase this problem with every single CA ive worked on not just my own.

this year alone i think i have thrown out 5 CAS sensors and two or three exhaust camshafts. cant wait for my megasquirt to be finished so i will never have to deal with that crap again!!

PS any one have a TPS plug off a old KA or CA harness i could really use one!!

[Trigger]

timing in the motor is dead on so i would say its a sensor doing it. I just put a brand new temp sensor on so i dont think thats it. i will check that cas though i think that could be at fault. thanks for the info

Tim

[boost_boy]

timing in the motor is dead on so i would say its a sensor doing it. I just put a brand new temp sensor on so i dont think thats it. i will check that cas though i think that could be at fault. thanks for the info

Tim

Your tps causes this and most times doesn't produce a code. If you have the harness connector just sitting there without the retainer, it will move around and will cause your rpm to surge as well in which naturally, will make your timing change, too.

Dee

[boost_boy]

If your car is running like crap, then suspect the CAS because it too can be faulty and not flash a code. These guys are on the right track, but I will go the cheaper route and watch the TPS first.

Dee

[Trigger]

yeah i was thinking the tps because i changed it out a couple weeks ago because i thought it went bad but come to findout it was my temp sensor so i have been thinking of what all has been changed and the tps came to mind and as we all know a bad tps will make the idle surge like its doing. so I will change back to my old one and see if that makes a difference. Thanks

Tim

[Trigger]

ok i think we might be on the right track. i changed to the old tps and it idled at 1000rpm's. I didnt try to set the idle but i am sure i could turn it down to 850rpm's but when i engine got warm all of a sudden it was like someone just stamped on the throttle the rpm's went up and kept going up until i turned the car off. I checked codes and was getting 13 when it was warming up then right before it reved high the 13 changed to 55. so i am going to try a buddy's tps that is on his running car and see if it does the high rev thing again if it does then i am going to recheck the temp sensor. any other idea's guys?

Tim

[boost_boy]

ok i think we might be on the right track. i changed to the old tps and it idled at 1000rpm's. I didnt try to set the idle but i am sure i could turn it down to 850rpm's but when i engine got warm all of a sudden it was like someone just stamped on the throttle the rpm's went up and kept going up until i turned the car off. I checked codes and was getting 13 when it was warming up then right before it reved high the 13 changed to 55. so i am going to try a buddy's tps that is on his running car and see if it does the high rev thing again if it does then i am going to recheck the temp sensor. any other idea's guys?

Tim

Do you have the retainer on the harness connector for the water temperature sensor? If not, you may want to put it on. Or it could be the plug is bad or have some corrosion in it.

Dee

[Trigger]

i pulled a temp sensor from a running ka24e motor so i will install it tomorrow and see if that changes anything. If that doesnt fix it then i am going to try wiring it to the ecu and making sure there isnt a wiring problem in the harness. i will update tomorrow.

Tim

[Trigger]

hmm i get code 13 until it warms up then code goes away. i got her idleing though today but it was a little rough so i looked at vacuum and she wasnt pulling but 0-3 so i am going to go back over everything and look for leaks again

[Trigger]

hmm a little confused...well i rewired the temp sensor and how its showing 13 at all times. I have the one from a friends are in it now which has been throwing the light the whole time so when the engine cools down i will switch to the new one and see if that doesnt fix it. but she is idling alot better now and also after i rewired the temp sensor my air/fuel gauge started working...im thinking the ground has something to do with it. maybe the wire was bad going to the temp and it was throwing everything off.

[Trigger]

ok i just cleaned the maf and checked my coils and the car is running like crap. you crank it and you have to play with the throttle to keep it up and running, its running super rich, and pulling maybe 3 pounds of vacuum...any ideas because i am ready to shoot myself

Tim

[Trigger]

changed the vacuum lines to the diagram sean posted a whiles back and that fixed the vacuum. Now the only problem is its running really rich and idling high. I think those are going to go hand in hand though so if i fix the richness then I should be able to fix idle. I have a walbro 255 with stock fpr and stock injectors with a t3/t4 turbo...think i should upgrade fpr?

Tim