10 degrees retard; how bad is that? how to fix?

[hodgeofflo]

I hooked my 87 Turbo T to a scanner, and I am getting 10 degrees of retard at max boost of 15 lbs. At the suggestion of my mechanic, I got a high perf fuel pump, adj fuel press regulator, and put a new fuel filter on, but that did not help. The fuel pressure is set correctly, and it is increasing 1 lb of pressure for each lb of boost. I have also done the full "spring cleaning tuneup", including all filters, plugs, wires, oil, tranny fluid, etc.
I just want to get the car to good stock condition. I don't want to add alky, and would rather not change the chip, both of which are my mechanics next suggestions.
Any suggestions on what else I can do?

 

[325DR]

What octane gas are you using? I hope 93? 10 degrees is a lot and can destroy the engine (at least the head gaskets). Do you have an adjustable wastegate?

I would put in some 100 octane unleaded and see if the KR goes away. If it doesnt, then you know you have other problems.

 

[BLACK6PACK]

Sounds like you have a pretty smart mechanic! Thats a rarity!! Every suggestion he has made is a good one. Its not such a good idea to use alky to mask a problem though. I would bet that the chip is the problem. I don't know why you wouldn't want to change it. You can get one for $25 and it takes 2 minutes to change. Much better than $4000 for an engine rebuild. You should also hotwire the fuel pump.

 

[hodgeofflo]

Do you think there is a problem with the stock chip? I do not want to modify the car, that is why I am trying to avoid replacing the chip. Is the $40 cost you are referring to the cost of a stock replacement chip?

 

[bandwidthpolice]

Increase the octane of your gas. Put 10 gallons of 93 in with 3 gallons of xylene & a shot of tranny fluid or Marvel Mystery Oil. If the knock goes away, it's probably timing. If it still exists, it's probably false knock attributable to other things (knock sensor too tight, exhaust loose, etc.).

BTW, what is your fuel pressure? Mine knocked like crazy when I went overboard once (46 lbs of FP) .

 

[Nojug]

I agree w/ the banner above mix some xylene w/ your 93 it wont hurt your o2 and its a good octane booster. Try that and see if it goes away if it does something is still off you should be able to run 15psi on a stock chip w/no knock. Also check to see if you were picking up the knock on a gear change my car would false knock if I stabbed it from a 55mph roll because it would downshift to second but from a dead stop it would not knock. Oh and check to make sure the exhuast is not hitting the floor.

 

[Eric Stage I]

The stock chip has about 23* of timing. You probably will not be able to run 15psi and 23* on pump gas without getting some knock retard. I would get an aftermarket street chip which will have more like 18* timing.

Eric

 

[bradofflorida]

Thanks for all of your tips. I know what to do now. I will post the successful story when it is over.

 

[gnXfan]

And don't worry about not being stock. An aftermarket chip from Jim Testa and a 160 degree stat are easy to swap back and can have the car idle better and be safer running than stock.

 

[Matt Weiser]

Originally posted by Eric Stage I
The stock chip has about 23* of timing. You probably will not be able to run 15psi and 23* on pump gas without getting some knock retard. I would get an aftermarket street chip which will have more like 18* timing.

Eric

Wow, is there really that much timing in a stock chip? I had no idea. That could explain my knock problems, too. I'm getting 10+ KR at part throttle on 91 octane California gas on a stock chip with boost at around 14 psi. I'm showing real rich O2s (~850) when this happens so I've been exploring whether it is "rich knock." I know it's not false knock because I can hear it, so maybe I just need a new chip to take some timing out...

 

[750H.P.V6]

91 octane gas sucks

Matt,

The gas here in CA is not doing you any favors and the idea of getting a more conservative chip for your car is probably a good one. I have an '87 Limited as a daily driver and I use a chip with 17 degrees timing at WOT. I still get knock retard.

Based on what was stated above I have to add my $.02 and say that 10 degrees of KR isn't going to blow up your engine but it isn't a good thing either. It's quite common to get a spike of KR at the shifts on a stock car with a stock 12" convertor. Usually you will see a high KR# then a trickle down effect in the following frames.

Personally I don't like to see more than 5 degrees KR on a shift but I use a 3rd gear pull as my benchmark. If there isn't any KR in 3rd and the A/F ratio is good (lets say 800mv or there abouts) you'll be fine. BTW, the stock chip has 22 degrees timing at WOT not 23.

Neal

 

[Eric Stage I]

22 degrees on the main table, plus 1 on the coolant advance correction table (assuming the coolant is 175-180*F). If the coolant is even colder, like 160*, then you'll be up around 23.5 degrees total. If the coolant is up around 200*, then you'll only have 22.

Thats where I was getting the extra degree from.

Regards,
Eric

 

[750H.P.V6]

Eric,

I wasn't knocking your info and based on what you just added that sounds about right. Basically too much timing for the available octane and boost level. The other point I was getting at is that a few degrees or KR on a shift isn't going to kill anything.

Neal

 

[Eric Stage I]

Neal,

No "knock" taken (pun intended).

I often wonder if the factory purposely went too high with timing knowing that the "right" amount would be pulled with knock retard. If you've got a 22 degree chip, and you get 5 degrees retard, you've instantly got a 17 degree chip. Maybe they felt no damage is done in that first instant that knock occurs as long as the timing is pulled fast enough. I dunno...

Eric

 

[TClassic]

MASS-AIR, a bad Mass-Air will cause More & more knock retard
as it goes bad, and your idle BLM's will/could be low.

At least that was my problem, after going through installing TWO fuel pumps, cleaning & flowing injectors, swapping regulators,
and going NUTS trying to figure out a Top End LEAN-OUT.
Here it was simply a BAD MASS-AIR, only pegging 230-240gps and causing Lean-out!

 

[turbolimited]

Wiped cam lobe will cause that too. If all else fails, pull the valve covers and eyeball the rocker shafts (while car is running or cranking the starter). If a cam lobe is shot, you'll know.

 

[Matt Weiser]

I've got a Joe Lubrant chip with 20* timing built in. Maybe I'll give that a try and see if it helps at all, at least it's a little less timing than stock. But it sounds like I probably ought to go with a custom chip anyway.

Neal, I seem to recall that somebody mentioned you burn chips. True? Since you know about our crummy CA gas, they recommended your chips. I'm not looking for anything radical, just a nice daily driver upgrade chip that won't give me any trouble. Fill me in...

P.S. -- I recently installed a Power Plate to try to deal with this problem, and it helped some on the low end, but seemed to shift the knock problem up into higher revs/boost.

 

[750H.P.V6]

Matt,

You're correct I do make chips and I also have to put up with our crappy gas too. Drop me an e-mail and we can chat. Hopefully I can help.

Neal