Sluggish off the line and worse in hot weather

shadetree_v70 · Post by **shadetree_v70** » 12 Jul 2018, 19:54

Can’t figure out what’s going on. Starts and idles just fine. Drives and shifts fine. But there’s just no real power until about 3000rpm.

A while back I posted my saga of lower engine noise, and decided to swap in a lower mileage motor instead of trying to rebuild. Got it all back together and drove great. Except that stupid me forgot to install the front pump seal in the tranny, which leaked like a sieve on the test drive. After 332000 miles how else would it be? So I replaced that seal, buttoned it all up again and on first drive noticed significantly less power. Seemed like lack of boost. No smoke, noise, leaks, just no low end power. I have tracked down every vacuum line swapped in a space TCV I had, swapped in a newer CBV diaphragm, can’t figure it out. The car is driveable but slow off the line. Gets worse in the heat (it’s been mid 90s lately). I’m starting to think something electrical? I’m tempted to swap turbos? But the damn thing ran just fine as it sits before I changed that tranny seal so I feel like I didn’t hook something up correctly and hoping to get some fresh ideas to get this resolved. Thanks!

Post by **mrbrian200** » 13 Jul 2018, 11:32

I doubt it's electrical. Beyond that it's difficult to speculate considering you've dropped the trans twice.
If there are no OBD/DTC trouble codes or CEL lit, my best guess would be an issue with the torque converter.
However, even with that I would expect the TCM should be picking up on the discrepancy between the input and output shaft speeds and trigger the CEL and limp mode.

Are you certain the shift select cable is attached/adjusted properly? ie. the dash indicator may say it's in "D" but the trans is actually running in "3"? I'm not sure if that's even possible...just a thought.

'light power' until pushing a higher RPM sounds like my car if I put it in 'Wet/Winter' mode where I believe the trans starts out in 2nd gear instead of 1st.

Edit: you ran it with a badly damaged or missing pump seal. Might there be a first fill procedure that might need to be executed to purge air from the internals/valve body/servos?

shadetree_v70 · Post by **shadetree_v70** » 13 Jul 2018, 13:14

The only "electrical" i could think of is underpowering the coil or something like that but I realize that's a reach. It was running fine before trans drop #2.

I will check the shift cable. I was very careful to mark exactly where the bracket was bolted but I hadn't thought of that thanks.

Much like a fresh coolant fill, there was a bit of check/top off/check/top off process. I was surprised how much i had to add after the first test drive around the block. It's full now and not leaking, so at least I have that

The CEL is on intermittently but that stems from the air pump. It used to be on all the time, with the new motor sometimes it doesn't light at all. No different codes present.

Post by **wizechatmgr** » 13 Jul 2018, 22:25

When my MAF was dirty, I had the same kind of lethargic response.

jsloden · Post by **jsloden** » 14 Jul 2018, 12:38

This is probably not it since you said it started when you swapped the engines but when I first purchased my c70 it was much more sluggish then I knew it should be. I did a drain and fill on the transmission and realized that it was about two quarts low. filled it up to proper level with new fluid and the car picked up significantly. The trans wasn't slipping or anything, just really sluggish. May want to at least check the level.

Post by **sleddriver** » 15 Jul 2018, 19:40

1. Be sure your timing belt marks are spot on. Mine was 'detuned' for nearly 6yrs when indy mis-installed it 2 teeth off and turned it into a dog. Tooks years to make the connection.

2. If it's very hot there, you need premium gas (93) otherwise the ECU will retard the ignition enough to dump most boost and turn it into a dog.

3. Ensure your wastegate is properly set. Again, mine was severely off for about 14yrs before I ever thought to check it. In a turbo car, that's just nuts.

4. Smoke the motor looking for vacuum leaks.

Post by **abscate** » 16 Jul 2018, 03:28

I crossed up my turbo vacuum lines on the T5 and drove it like that for about a year. Never quite understood what happened as my vacuum pull off for the Compressor pull off wouldn’t reach from manifold to valve, had to buy new hose.

I’m a light footed driver so I didn’t notice performance loss. Someday, someone will buy my T5 that has had the little old lady’s life.

shadetree_v70 · Post by **shadetree_v70** » 16 Jul 2018, 06:36

sleddriver wrote: ↑15 Jul 2018, 19:40 1. Be sure your timing belt marks are spot on. Mine was 'detuned' for nearly 6yrs when indy mis-installed it 2 teeth off and turned it into a dog. Tooks years to make the connection.

Done. Before I set the new motor in place I notice they weren't spot on. They are now

2. If it's very hot there, you need premium gas (93) otherwise the ECU will retard the ignition enough to dump most boost and turn it into a dog.

It's never been an issue before but good thought to keep in mind. I always thought turbo motors typically run lower compression and don't detonate as easily as n/a motors.

3. Ensure your wastegate is properly set. Again, mine was severely off for about 14yrs before I ever thought to check it. In a turbo car, that's just nuts.
Will double check

Post by **sleddriver** » 20 Jul 2018, 15:42

Perhaps you pinched a seal or vacuum hose or connector didn't fully seat, causing a vacuum leak. I recall RSPI warning people about intake manifold gasket leaks and the havoc they wreck.

Save time, frustration and your hair by smoking it.