C5 Vette 4l60E Help - P1870 with 3.15 gear and 2800 Stall

[adamlewis82]

Hi all,

I'm after a little bit of help again with my tune, this is my 2nd time around with a rebuild and I don't want to break it any more...I wondered if anyone was free to have a glance at my tune and logs to see if i'm doing something wrong as after stall and gear swap and fresh rebuild i'm getting a 1870 code after about 30mins of driving and only when up a long hill...(always on my drive home from work)

I've done some logs if you could look at and see what's happening, but i'm trying to log slip which is obviously which is causing this, but in 3rd gear my input and output shaft speeds can read true but still getting some slip, and when locked in 4th i'm about 200rpm of slip...from what i understand this should be zero?

The drive itself is behaving perfect, but with it being rebuilt for the second time of burnt band and burnt 3/4 pack i'm over cautious....it shifts nice and firm for most of the driving, but when going up a long hill after 30mins of driving it drop out of lockup, I check codes and its p1870...I clear it and its back to normal and locks up again fine and stays that way.

My worry is that after logging is all this slip and input output speeds not matching.

I've vacuum checked the valve body, no leaks now...the TCC bore is sealed with the fitzall tcc valve, AFL bore checked and no leaks, no other leaks in any of the valve body...pump surfaces are machined and new slide and pump internals, no cross leaks....all clutches air checked and input drum tested for leaks.

Build list:


Boss hog 2800 Stall convertor (flushed from last time- 3 months old)
Alto 3~4 Powerpack
Alto Red wide band
New reverse input drum
Beast sun shell
Moulded pistons
New 13 Vane pump and slide and vanes
Raybestos fwd and over run clutches
Sonax super hold 2nd servo
Sonax super hold 4th servo
Sonax pinless accumulators all round
Sonax Extended boost springs for input drum
Transgo fwd and rev abuse bore plugs
Transgo Separator plate
Transgo HD2 shift kit
.500 Boost valve
All seals and paper replaced

There's probably more but i've forgoten.

Clutch clearances 35thou for 3-4 and 45thou for forward...everything assembled fine and first start was good.



Line pressureHot)

Idle 60psi
Reverse 90-120psi

Driving D = 80ish psi
On Throttle driving = 120 psi
3/4 Throttle = 200 ish psi not tested WOT as still running in for 500miles....i've done 250 miles so far now for this log.


I just can't see why I'm getting so much slip? I've used blue cat tool for values for the tune with changing gear ratio and stall...is my new converter knackered or does it just need more pressure adding in the lower load section of force motor table? or would a new harness for the TCC solenoid fix it, as already done the 1870 fix for the valve bore so isn't that.

I hope someone could shed some light as I just want to be able to relax with the car and enjoy it!

Have I got the logging inputs correct for what i'm looking for on hp tuners? Just going of recommended suggestions.

Many thanks!

23-07-10 12-44-32.hpl3.15 Gear Change, shift points v3 and new force motor v4.hpt

[bthurman65]

I dont see your log. have you done anything to the motor as far as upgrades. 1 thing I saw in tune was shift times are really high. Are doing anything with the car other than just driving. Racing, track? I like to see shift times set at .200 all of them. You will get fast, firm shifts.
Post your log

[bthurman65]

sorry, i found the log. you need more data. need to see TPS, RPM, Speed, Current Gear, then data log all the transmission PID's
Not being a ass, but is the TC a lock up converter?

[adamlewis82]

sorry, i found the log. you need more data. need to see TPS, RPM, Speed, Current Gear, then data log all the transmission PID's
Not being a ass, but is the TC a lock up converter?

Hi mate, thanks for the reply....motor wise its a stock 5.7 LS1, it won't be seeing a track just a bit of back road enjoyment....I've just amended the tune with your suggestion and made all shift times 0.200, id over looked those as i've rolled back to an earlier tune and not changed them, so thanks.

and convertor wise it is a lock up converter, its a boss hog night stalker one....it locks up great, nice and sharp engagement until it throws this 1870 code, once cleared it locks fine again...just worried about all this slip its showing.

My log should show rpm, speed, torque and current gear, trans slip math, tcc slip, input/output shaft speed.

Heres a screenshot of how it looks...C5 Log2.jpg

[adamlewis82]

Other grab C5 log.jpg

[blindsquirrel]

Super-simple yet excellent and also totally free screenshot program: https://www.snapfiles.com/get/lightscreen.html

I have mine set up for shift+backspace, that automagically dumps an image of the current window into a dedicated folder. All the wiring diagrams & pinouts I post here are done with this little tool.

[adamlewis82]

Super-simple yet excellent and also totally free screenshot program: https://www.snapfiles.com/get/lightscreen.html

I have mine set up for shift+backspace, that automagically dumps an image of the current window into a dedicated folder. All the wiring diagrams & pinouts I post here are done with this little tool.

Thanks for that buddy, will use that next time! I don't know if you remember but you were helping me last time when I was having an issue with 2nd and 4th, it ended up being a full rebuild again... Running great apart from all this slip.... Well it doesn't sound like it's slipping, sounds fine....but input and output shaft don't match so showing as slip? I think I've done the gear calculator correct, speedo is accurate withing 1mph.

[blindsquirrel]

Are you looking for slip between engine RPM & input shaft RPM (this will pinpoint the converter), or between input & output shaft RPM (trans internals)?

[adamlewis82]

Yeah I'm pretty sure it's the converter that's showing up as slip, as when logging actual trans slip in gears 1-3 it's mostly reading 0 rpm.... This was a math parameter worked out with input/output and calculated gear ratio.

Where as in 4th gear locked I'm getting about 150-200rpm slip.... Just didn't know if there's any vss pulses or whatever places I need to adjust to get it to read right or unless it is actually slipping? It's a fairly new converter so shouldn't be toast already?

[Alvin]

I haven't read every word in this post but just a FYI. It was pretty common for LT1 (92-97) PCM's to do this. I feel like I've seen it myself in a few early GEN 3 OS. But anyway the fix was to raise the min temp for trans component slipping so that the test never ran.

[adamlewis82]

Ah ok, Brill cheers... I had seen that part in the tune area, but wasn't sure if it was safe to do that, least that will stop it coming on.

I've done some more logs and found I'm not getting any trans slip when getting on, it's holding fine.... It's just the amount off converter slip it's showing when locked now I'm reading how bad it is, just want to find out if it's genuine slip or just a calculation.... Doesn't sound like it's slipping bit I guess maybe a wouldn't hear 150rpm?

I haven't read every word in this post but just a FYI. It was pretty common for LT1 (92-97) PCM's to do this. I feel like I've seen it myself in a few early GEN 3 OS. But anyway the fix was to raise the min temp for trans component slipping so that the test never ran.

[Alvin]

You should be able to calculate the slip yourself to be sure. I've setup RPM/MPH maths then look at them on the line display. It will not mean much until the converter is locked but you can at least see if that ratio is moving which would be a slip. I can't think of a situation where it would slip 150 rpm all the time. If it's actually slipping I would assume it would slip more if you leaned on the throttle.

[jhbau1000]

Sorry I was in the wrong thread guys.

[adamlewis82]

You should be able to calculate the slip yourself to be sure. I've setup RPM/MPH maths then look at them on the line display. It will not mean much until the converter is locked but you can at least see if that ratio is moving which would be a slip. I can't think of a situation where it would slip 150 rpm all the time. If it's actually slipping I would assume it would slip more if you leaned on the throttle.

Nice one Alvin, been at work all this set so not had chance to log the car, will try setup those maths and see what I can find! Like you say surely after all this time is would be showing more slip and getting worse but it just seems to hover around 150 to 200 all the time no matter what input... Obviously it's up to 1500 when it's unlocked when accelerating.

Cheers for the help I'll get some data now I'm off work 👊