badazzquest Posted March 26, 2012 Report Share Posted March 26, 2012 The car was running poor. I have been SLOWLY ironing it out and getting better very little at a time. One thing that I did was rebuilt the TB with the correct Felpro base gasket and new shaft seals. Rebuilt the dizzy and the correct advance. I have been trying to figure out a spark knock at throttle tip in/ cruising speed, AND hesitation/stumble 3000-4000. While double checking that the vac advance is on the right port (the closest towards the radiator in the row of 3 under the TB), I found vacuum on that line, going to the Dizzy. It isn't very much, but it is still there. The vac amount increases as engine revs like normal. With the vac plugged, the spark knock went away. I didn't drive it to check the hesitation. I unplugged the IAC, slackened the Throttle cable to make sure the throttle wasn't partially open. Why is the vac on that line at idle? Link to comment Share on other sites More sharing options...
topher87 Posted March 26, 2012 Report Share Posted March 26, 2012 cause its a vac advance at idle and retards under boost disconecnt the vac line and check your base timing should be 10 degress befor top dead center T87 Link to comment Share on other sites More sharing options...
Indiana Posted March 26, 2012 Report Share Posted March 26, 2012 There's not to be enough vacuum on that port at idle to make a difference is the hose is connected or not. The opening inside the throttlebody bore is above the throttleplate when its idling properly. What is done to this car and what rpms does it idle at? Link to comment Share on other sites More sharing options...
badazzquest Posted March 26, 2012 Author Report Share Posted March 26, 2012 It is idling @800-900. The base timing is at 10btdc. Even tried it at 8-6-4 and 2btdc and lost power obviously. The knock went away at 2btdc Link to comment Share on other sites More sharing options...
Indiana Posted March 26, 2012 Report Share Posted March 26, 2012 That ISC screw is the motor position sensor adjustment screw and the idle motor after the CTS tells the coolant is hot ends up with it in a very small rpm window. Your fixed screw is in too far or the throttle cable too tight or its running poorly from dirty injectors/wrong injectors/fouled plugs or a compression/valve train issue. Seems you have to set the throttle plate open too far so it will idle and that's exposing too much vacuum too near that port. The only other way is if the tab on the linkage where the idle motor tip switch makes contact is bent from where it was originally and someone would had to have did that purposely. Link to comment Share on other sites More sharing options...
badazzquest Posted March 28, 2012 Author Report Share Posted March 28, 2012 I hold the throttle open about 1500-2000 and get it to knock. I pull the dizzy VAC line off and it instantly goes away. Touch the VAC line back on the advance nipple and it knocks again. The motor is stock with balance shaft yet. About 100k on it. Compression is 110#-112# in all 4 holes. I am stumped. Link to comment Share on other sites More sharing options...
Indiana Posted March 29, 2012 Report Share Posted March 29, 2012 (edited) You described it better but its not timing, you got a fuel problem unless your cam timing is off. What are you using for injectors, are they cleaned, are the clips new, your fuel pump, filters etc and have you checked fuel pressure? A stock primary injector has the letter L stamped on the side of it and the plastic portion is black and I'm assuming you have an 87+ car. Edited March 29, 2012 by Indiana Link to comment Share on other sites More sharing options...
badazzquest Posted March 29, 2012 Author Report Share Posted March 29, 2012 It is a 88. The injectors have been replaced with non-leaking and bench cleaned ones. There were Trilogy in it and the same problem. Clips are new. Injectors are in correct location and plugged in correctly. Fuel pressure is good. Gauge tapped to windshield. Adjustable FPR and set it higher and lower in increments and no change noticed. The timing chains are original and never been off since it was running in the donor car. Link to comment Share on other sites More sharing options...
badazzquest Posted April 12, 2012 Author Report Share Posted April 12, 2012 Finally got a AEM wideband installed. It wants to run lean....like 10.0 Thats when it knocks, obviously. It will run 13-15 and its ok but it will eventually go back to the bottom of the gauge and sit there. Link to comment Share on other sites More sharing options...
scott87star Posted April 13, 2012 Report Share Posted April 13, 2012 That's backwards, 10 is rich, anything above 15 is lean. Knocks, you can hear this knock or are you seeing something? I very much doubt a true engine knock at tip in or cruising speed. Please describe this phenomena better. Link to comment Share on other sites More sharing options...
Indiana Posted April 13, 2012 Report Share Posted April 13, 2012 You can't clean injectors at home. You have an ultrasonic cleaner and a device to cycle them for about an hour continuously? Spraying crap in them does nothing. A lower mileage car has the worst injectors because they just sat there. You ever grow rock candy? This is what happens inside there when the fuel is just sitting. There's rust in that fuel I guarantee it. The minerals in there bond to the metal and there's corrosion from where the aluminum parts are touching the steel parts and this crap sticks to the surfaces and it doesn't wash off if you used a pressure washer and 50 gallons of brake cleaner you have to have it removed with an ultrasonic cleaner and that is the ONLY way to remove it. You'll never get the proper amount of fuel to dispense with dirty injectors. You'll never have the correct shape and atomized spray pattern either. You ever use an untrasonic cleaner you'll know what I'm talking about and no not those little tiny things you clean your jewelery at home in there are no where near powerful enough. Link to comment Share on other sites More sharing options...
badazzquest Posted April 13, 2012 Author Report Share Posted April 13, 2012 Running that fat will make it knock? That will explain the lack of power and stumbling. I had brand new Trilogy injectors in it when I got the car and it ran like crap. I guess sending them out to get cleaned is the next step. I just bought these stock injectors last year. The guy said he put them in his car to make sure they were good before he shipped them. Link to comment Share on other sites More sharing options...
badazzquest Posted April 30, 2012 Author Report Share Posted April 30, 2012 I ordered new injectors from Brian @ Lowershores Performance. Great guy to deal with. I dropped the tank to flush it before installing the new injectors. I found a few sins. The previous owner installed a new pump but its the one that is to small and has the rubber wrap to take up the extra space. The fuel dampener is rotted through and Im surprised it isn't leaking. You can push on the internal spring in the dampener. He also cut the pressure hose and spliced it back together with 3/8 brake line. What is the best way to fix it? Go with a Walbro 255 and replace ALL the lines with AN fittings and braided? I am planning to mod the car as time and cash allow. I am still having the same drivability issues but found these problems. I have good FP currently, but I need to fix this stuff for the fuel system. Link to comment Share on other sites More sharing options...
badazzquest Posted May 28, 2012 Author Report Share Posted May 28, 2012 Installed the Walbro, eliminated the check valve at the pump. Flushed the entire fuel system. Rebuilt the TB and forn the previous owner who powder coated the TB had assembled the TB and put the butterfly in upside down. Installed the injectors. The knock at tip in is gone!!!! Now when you hold it above idle (1500-3500), it will rev then stall out until the rpms drop to about idle then rev back up. THe wide bad goes full lean, of the scale, then come back into range at the same time the car is surging. Fix one thing and another shows up. I think this car is cursed. Does anyone know of a good exorcist? Link to comment Share on other sites More sharing options...
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