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AE92 Corolla GTS
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75 Posts
Discussion Starter #1
I have a silvertop engine running with a blacktop ECU but it seems to be running very lean. I've checked my timing and it seems that it only runs properly if it is advanced by about 15 degrees. My crank, cams, and distributor all line up properly at TDC so this leaves me a littled baffled.

Could this be a fuel pressure issue because I'm still using my original AE92 fuel pump?


Anyone have any ideas?


MississaugaGTS
 

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Resident asshole
Corolla
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9,552 Posts
how do you know if its lean? and I think if it is, then the blacktop ECU is to blame, those two engines are different in characteristics.
 

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AE92 Corolla GTS
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Discussion Starter #3
The plugs are white and very clean like it has been running too hot. I've heard that white plugs means that the engine is burning coolant. I don't know how true that is but my rad fluid level is OK.

How different is the blacktop ECU? I know it has cleaner fuel curves and the engine has a higher comp ratio. but I think the O2 and MAP feedback should beable to compensate for the differences.

Please correct me if I'm wrong. Any info is greatly appreciated!
 

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Resident asshole
Corolla
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The plugs are white and very clean like it has been running too hot. I've heard that white plugs means that the engine is burning coolant.
Uhm, white plugs nowadays can mean the mixture is ok. Only way you can judge if the mixture is too lean is go to get an exhaust gas readout, it'll give you very high detailed analysis of your mixture. Oh and white plugs definately dont mean you're burning coolant.

How different is the blacktop ECU? I know it has cleaner fuel curves and the engine has a higher comp ratio. but I think the O2 and MAP feedback should beable to compensate for the differences.
Different fuelmaps.
 

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AE92 Corolla GTS
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Discussion Starter #5
Maybe I'm worried about nothing....but to be sure I guess I could hook up an air/fuel mixture gauge and double check my fuel pressure.
 

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Druken Postwhore
AE92GTS
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im thinking the ECU also....its a different fuel maps... black top is measure by Manifold Absolute Pressure (which measure the volume of oxygen) and silver top is measured by Air Flow Meter (which is measure by the flow of the air) wiring is probably not connected right.... if you are using ITB's with out the intake box, that could also cause other issues.
 

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Resident asshole
Corolla
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but to be sure I guess I could hook up an air/fuel mixture gauge and double check my fuel pressure.
A/F meter is accurate enough for a thorough mixture check, it'll only give you a general idea, especially if its a led meter. Numerical A/F meter with a wideband o2 sensor is a better setup, but they are hard to find.
Fuel pressure in itself wont tell you if the car is running rich or lean. In a fuel injected car, the car wont really run that well if you have low fuel pressure. I'm telling you this one more time, go take a thorough exhaust gas analysis, that should tell you what kind of condition the engine is running.
 

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AE92 Corolla GTS
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Discussion Starter #8
Thanks for the feedback guys....it's greatlyappreciated!!

So far the engine seems to run pretty well, but I did the entire swap by myself. If someone who knows how this engine should run was willing to take it for a spin for comparison sake, I would be interested in hearing what they think.

TRDragoon

Your probably right about the ECU. I have changed the wiring to include a MAP sensor and I removed the AFM. I tested the MAP sensor and I know that it works properly. There must be something that I have accidently overlooked.


Flashman

I guess I'll have to pull my head out of my lazy ass and get the exhaust tested!!! It's the only way to really know what's going on here! Thanks!
 

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Resident asshole
Corolla
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yeah get the exhaust analysis and then you can see if its running rich or lean. They'll put a lambda sensor in the ass of the car.. oh yeah, get it to a place where they know what they are doing. Since catalytic converters can give out mixed readings.
 

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AE92 Corolla GTS
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Discussion Starter #10
These days it's hard to find a garage that will give you the service you want without trying to make money off your ass, but, I'll see what I can find around Mississauga!
 

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1992 Corolla, 1.8L bored and stroked to 1.9, with Silvertop head running ITBs megasquirt ECU, 6speed
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What year is your car? I am thinking about swapping in a 20v into my 99 corolla.

thanks
 

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MississaugaGTS said:
These days it's hard to find a garage that will give you the service you want without trying to make money off your ass, but, I'll see what I can find around Mississauga!
Are you using the blacktop IAT sensor on your setup? It's located on air filter box and measures the intake air temp, on the silvertop 20v this function is performed by the AFM.

If you're still stumped, try calling Luis or Ulyses at Applewood Auto Services (905)275-1919. They're on the north east corner of Tomken and Bloor in Mississauga and can diagnose any 20v problem.

Let them know Derek referred you!
 

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Immortal
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332 Posts
He's probably running the blacktop ECU cause it's MAP based and eliminates the AFM (open ITBs). If anything... I'd figure the silvertop would run really rich on the blacktop ECU. The general rule is... the engine boggs when very rich and backfires and misses when lean. If you have a voltometer... you can check the O2 to see if it's rich or lean... then again, the O2 can also be the cause. Best bet is to get CO readings from the tail pipe... this can probably be done at a smog station for free...
 
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