Down on power, detonation, burning pistons - NEED HELP

[Jerryl]

All that work and never bothered to test the fuel system.. Tisk-tisk.

Rick,
You are 100% correct!!!

Let’s also not lose sight that the “shop” told him it was a timing issue and the injectors are “good to go”. I am sure if the OP had any inclination of the "cause of and affect of fuel system delinquencies" on these cars, the fuel system would have been tested. :redface:

Sometimes people just don’t realize some of these things, especially if there is no “charged system experience”. These cars do not tollerate deficiences if a given performance is expected, period.
It’s called the school of hard knocks right? :wink:

 

[edmonds27]

So are you guys saying that this looks more like a lean fuel condition instead of a timing problem? (Actually it wasn't the shop that said it was timing, that was the guy that builds my late model engines AND the guy that does all our machine work.)

We tested FP at the fuel rail once just sitting in the garage and it was good although I don't remember what it was (been a few months ago). We fired the injectors with 12 volts and they all had good spray. (I have a friend that works at the "shop" and that IS where we tested the injectors and the same way they test all of their injectors. Now, as i confessed my engine building/troubleshooting experience is carbed SBC, but it seemed like a reliable test to me. Beyond that, no we didn't "test the fuel system?". Aside from testing voltage on the harness or buying a PL what else should we have done?

Sorry if that sounds defensive, it's not intended, I certainly don't want to make the same mistake twice. So, as of right now the plan is (as mentioned above): Engine reassembled, test voltage on injector harness, test FP again, upgrade to 87 ECM w/TT chip and MAF, add a PL. Anyone think we should do something different?

 

[edmonds27]

So are you guys saying that this looks more like a lean fuel condition instead of a timing problem? (Actually it wasn't the shop that said it was timing, that was the guy that builds my late model engines AND the guy that does all our machine work.)

We tested FP at the fuel rail once just sitting in the garage and it was good although I don't remember what it was (been a few months ago). We fired the injectors with 12 volts and they all had good spray. (I have a friend that works at the "shop" and that IS where we tested the injectors and the same way they test all of their injectors. Now, as i confessed my engine building/troubleshooting experience is carbed SBC, but it seemed like a reliable test to me. Beyond that, no we didn't "test the fuel system?". Aside from testing voltage on the harness or buying a PL what else should we have done?

Sorry if that sounds defensive, it's not intended, I certainly don't want to make the same mistake twice. So, as of right now the plan is (as mentioned above): Engine reassembled, test voltage on injector harness, test FP again, upgrade to 87 ECM w/TT chip and MAF, add a PL. Anyone think we should do something different?

 

[TurboBuRick]

The fuel system is everything on these cars. The injectors are only one part. There is allot to go wrong down the line. You have a fuel pressure regulator and a fuel pump that needs to be working correctly.

You can't guess. You need to test. Yes? :biggrin:

Is the fuel pump and regulator stock?

 

[Jerryl]

The fuel system is everything on these cars. The injectors are only one part. There is allot to go wrong down the line. You have a fuel pressure regulator and a fuel pump that needs to be working correctly.

You can't guess. You need to test. Yes? :biggrin:

Is the fuel pump and regulator stock?

These are some important questions, and Rick is 100% correct.
You can't guess, unless you like playing Rusian roulette.

......... Sorry if that sounds defensive, it's not intended, I certainly don't want to make the same mistake twice. So, as of right now the plan is (as mentioned above): Engine reassembled, test voltage on injector harness, test FP again, upgrade to 87 ECM w/TT chip and MAF, add a PL. Anyone think we should do something different?

No offense taken in your post, just a good tech discussion to get to the root cause.

There are two measurement needed with the fuel system; Pressure and volume. When the pressure increases, the volume decreases. We need to make sure you have pressure when the volume is needed since the fuel system “leak” is controlled by the injectors. This is the easiest way is the determine adequate pressure at XX boost. Example; The base fuel pressure is set to 43 PSI, line off. At 10 PSI boost you need to see 53 PSIG FP, at 20 PSI boost 63 PSIG FP (Line on of course). This is what guys refer to as: "FP rising with boost"
(Note(!): The stock FPR will not read 43 PSI line off, unless it has been upgraded)

If you don’t see the higher pressure, there is an issue that needs to be resolved. Some of the variables that affect FP are; Fuel pump, system and pump voltage under load, bad grounds, plugged filter, crimped line, defective FPR, inadequate or limited boost/pressure signal to the regulator, low fuel level, etc.

The only thing you did wrong was not monitoring KR. If you were, once you saw the KR, it would have warned you to get out of the throttle tp prevent damage at the lower boost levels.
My concern are the ring gap, and the KR sensor/module, but I don’t know. My logic is; If the KR system is working correctly, it would have probably pulled enough timing to just blow a HG, especially with a stock chip. Chuck Leeper who posted in this thread is one of the guru’s and could give a much better idea looking at the pics.

Throwing $$$ at these cars will not make it run better. The tune is everything. You do not need a MAF, until you determine it to be faulty. (PL will help you do that )

 

[edmonds27]

Dont I have to change the MAF if I upgrade to an 87 ECM?

 

[Jerryl]

Dont I have to change the MAF if I upgrade to an 87 ECM?

No . . . . Only if the current MAF is bad.

 

[Boost231]

jerryl, brian weaver and i where talking about MAF the other day.

Can you tell me the difference between the 84 MAF vs the 87 MAF.

I know i have heard some saying the 87 ecm swap doesnt work with the 84 MAF and others say it does. Seems kinda weird to me. Brian was telling me he had a 87 maf go bad and he put a 84 on there and it worked. humm

 

[Jerryl]

jerryl, brian weaver and i where talking about MAF the other day.

Can you tell me the difference between the 84 MAF vs the 87 MAF.

I know i have heard some saying the 87 ecm swap doesnt work with the 84 MAF and others say it does. Seems kinda weird to me. Brian was telling me he had a 87 maf go bad and he put a 84 on there and it worked. humm

There are two reports somewhere in the archives.
Some stated that their car runs better with then 87 style MAF, while others reported the opposite.
My recollection indicates that the 84-85 MAF runs slightly richer.
Possibly a different MAF curve. Don't kow why for sure but I have some other unconfirmed ideas to the "why".

Bottom line;
I do not believe and upgrade or upgrade will be more effective, if you have a good MAF.
The 86-87 design is different in design than the 84-85, but not necesarily required, IF the 84-85 is good.
Data collection is king here as well.

 

[Boost231]

goes to show, test the 84 maf and if it runs good use it. if not try a 87 maf

 

[edmonds27]

Thanks for all the info on the MAF. I think my MAF is okay, so that may save me a few $$$.

Ring GAP - I don't remember what all of them were, but I remember they were all between a tight .021 up to a very tight .024. Those should be fine right? We just got the new piston back in the hole and both the compression and scraper were right around .021 (1 a little more snug than the other).

In addition to the ECM possibly causing a timing problem I'd like to test my knock sensor. I've heard some people say to start the engine and peck the block with a hammer and listen for the timing to change. Surely there's a better way. I'd like to eliminate as many possiblilities as possible BEFORE we start the engine and begin doing damage. Can anyone tell me how to test one?

 

[edmonds27]

Thanks for all the info on the MAF. I think my MAF is okay, so that may save me a few $$$.

Ring GAP - I don't remember what all of them were, but I remember they were all between a tight .021 up to a very tight .024. Those should be fine right? We just got the new piston back in the hole and both the compression and scraper were right around .021 (1 a little more snug than the other).

In addition to the ECM possibly causing a timing problem I'd like to test my knock sensor. I've heard some people say to start the engine and peck the block with a hammer and listen for the timing to change. Surely there's a better way. I'd like to eliminate as many possiblilities as possible BEFORE we start the engine and begin doing damage. Can anyone tell me how to test one?

 

[edmonds27]

Oh yea JERRYL, about all those fuel system questions: I haven't tested most of that stuff yet other than to see that we had good fuel supply at the schrader valve, but I will definetly test the fuel system extensively this time. The fuel pump and regulator are stock.

Also, one more ECM question... I'm seeing 2 different model numbers for 87 ECM's, which one do I need? The part numbers I'm finding are 1226519 and 1227148.

 

[edmonds27]

Oh yea JERRYL, about all those fuel system questions: I haven't tested most of that stuff yet other than to see that we had good fuel supply at the schrader valve, but I will definetly test the fuel system extensively this time. The fuel pump and regulator are stock.

Also, one more ECM question... I'm seeing 2 different model numbers for 87 ECM's, which one do I need? The part numbers I'm finding are 1226519 and 1227148.

 

[Jerryl]

Pretty swamped right now, but here is a quick response.

Ring Gaps (From another thread)

3.800--3.830 bore
.017 top
.021 second
.024--.028 oil

Look for any oil residue in the cylinder.
Oil in the chamber on turbo cars don't play well together.


Fuel
Get a 237 Bosh Regulator from the junkyard, or adjustable FPR. You are looking for 43 PSI, at idle, line off.
Get a walbro or other pump, WITH a hotwire kit.
Get the injectors cleaned.

ECM
You want the 1227148

Knock sensor
You need a scantool. With the engine off, key on, tap the block in the back close to the knock sensor. You will see the KR, and you know if works.
You “may” be able to use a timing light, with the engine at idle, but it will be hard to make the correct determination as the timing jumps around. Scantool is still your best friend.

Pistons
What pistons are you using? Stock HA?

 

[edmonds27]

Thanks for taking the time Jerryl,

Yes the pistons are just the stock OEM replacement .060 over.

 

[edmonds27]

Thanks for taking the time Jerryl,

Yes the pistons are just the stock OEM replacement .060 over.

 

[edmonds27]

After taking a closer look at the knock sensor, it looks to be pretty old and the insulator is broken. I don't know how much those things effect it but since we KNOW we had a knock problem we decided to get a new one especially since they aren't all that expensive.

 

[edmonds27]

Well, guys I think I MIGHT have found the problem. I haven't been very hot on this thread lately... I was sick for about a week and just haven't had much time to work on it.

BUT, we finally got it put back together with a new 87 ECM and TTchip. When we tried to start it we had no fuel and no fire. I ran through the diagnostics tree from the "Sticky" and when I got to the point of connecting my multimeter to the cam sensor signal wire and turn the engine over the engine started! I shut it off and tried to start it again, no fuel, no fire. Ran the tree again and the same thing happened. Shut it off and tried to start it and again, no fuel, no fire. This time I skipped the rest of the diagnostic tree and just connected the meter to the signal wire and same thing. I unplug the sensor and I have the correct voltages on the harness, but when I plug the sensor in the voltage on the sensor wire drops from 8volts to 1volt (supposed to be 5 to 11 volts). I pulled the shaft out and turned it by hand with the key on and the voltage never changes just 1volt so I'm thinking my hall effect switch is bad. My question is - couldn't this sensor have been going bad for a while causing the timing problems?

 

[boostmaster]

Well, guys I think I MIGHT have found the problem. I haven't been very hot on this thread lately... I was sick for about a week and just haven't had much time to work on it.

I unplug the sensor and I have the correct voltages on the harness, but when I plug the sensor in the voltage on the sensor wire drops from 8volts to 1volt (supposed to be 5 to 11 volts). I pulled the shaft out and turned it by hand with the key on and the voltage never changes just 1volt so I'm thinking my hall effect switch is bad.

Incorrect. The voltage should drop from 7.5-8v to 0 volts. That's how you set the sensor. When the window is open you have voltage when the sensor moves past the window no voltage thus voltage drop. Don't waste your money on a sensor just yet....those things are expensive. Double check your double check.