Spoony Posted May 27, 2009 Share Posted May 27, 2009 i have a problem with my engine. im driving a t78 greddy kit with aem and 800ccm sard injectors. 2x walbro fuel pumps, 2 fuel lines. last year i was on a drag race. after going up to 1,6 bar my 4th piston melted. i replaced the engine this spring, started the search for the cause of the demage. i tested the injectors with 12 volts if they open and also how much ohms they have. seemed ok. then i found one of my walbros was spitting out fuel of the overpressure hole. so i thought this caused my demage. car was tuned up to 1,6 bar a/f was at 11,8 on the aem log. all other pistons looked good, just one with a hole in it. when i put in the new engine, also updated some 272 cams. put in a basemap and drove for 1 week with it. a/f was arround 10, much to rich, didnt go over 1,2 bar. then we started to tune the car. we lowered the fuel map until we had 11,5 on the log with 1,2 bar. after driving another log with the aem my 1st piston melted. my suggestion is one of the injectors is not 100% ok. i didnt put them in the same place of cylinders after testing them. yesterday i tested them how much they inject. i took 2,5 bar of water line and clicked them with 12 volts. stopped the time of 30 secs and injected the water into a bottle. they spray all the same and every injector put 0,3 liter in the bottle. so now im out of any guess what could be the cause of my demaged engines. its exact the same picture of demage. first 4th piston, now 1st piston. a/f log was good on both engine destroying runs. electronics where all the same, only changed the injectors into different places, so i thought this is the troublemaker. is there any other test for the injectors?? or where can i search? i dont want to break my 3rd engine! thanks eddie http://img39.imageshack.us/img39/8603/p1010889l.jpg http://img39.imageshack.us/img39/3356/p1010891i.jpg http://img39.imageshack.us/img39/3079/p1010894.jpg http://img39.imageshack.us/img39/9379/p1010888i.jpg Quote Link to comment Share on other sites More sharing options...
Alex Posted May 27, 2009 Share Posted May 27, 2009 Did you tune with Det cans? Do you have any det/knock recording/monitoring? IMO this smacks of a map that's not right... Quote Link to comment Share on other sites More sharing options...
Spoony Posted May 27, 2009 Author Share Posted May 27, 2009 the aem ems has a knock sensor detection that takes back the ingnition when its knocking. but with 100 octane fuel and 1,2 bar there is no knocking. the thing is, why is there always one broken piston and the rest looks good? first 4th now 1st. when the 4th broke it looked the same Quote Link to comment Share on other sites More sharing options...
bondango Posted May 27, 2009 Share Posted May 27, 2009 What size of injectors? what size of fuel lines? what type of fuel pressure regulator? are you monitoring/Logging Fuel pressure? I would be getting those injectors fully tested i.e. Flow and Spray pattern before re-using them. Quote Link to comment Share on other sites More sharing options...
Ryan.G Posted May 27, 2009 Share Posted May 27, 2009 the aem ems has a knock sensor detection that takes back the ingnition when its knocking. but with 100 octane fuel and 1,2 bar there is no knocking. the thing is, why is there always one broken piston and the rest looks good? first 4th now 1st. when the 4th broke it looked the same I wouldn't just relay on what you are seeing on the knock logs chap. A set of det cans should always be used!! Looks like a dodgy injector to me though. What injectors do you have? I would get a new set of injectors and flow test and clean them Ryan Quote Link to comment Share on other sites More sharing options...
Spoony Posted May 27, 2009 Author Share Posted May 27, 2009 i have 2 walbros, using one directly at the oem fuelpipe and the 2nd walbro got an extra 8mm fuelpipe directly to the other end of my oem fuelline with the injectors. the fuelpressor is an aeromotive and i have 3,2 bar fuel pressure. but the a/f was fine and if you run lean the other pistons get a demage too, not only one as far as i know. the injectors are from sard 800 ccm sidefeed for my uk spec. i tested them with water and open them for 30 sec. my guess is that one of them is not fast enought when they get in high revs and have to open/close very fast. but how can i test it? Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted May 27, 2009 Share Posted May 27, 2009 Thats classic det damage, i would also have the injector driver stage of the AEM checked as well as new injectors. Quote Link to comment Share on other sites More sharing options...
TLicense Posted May 27, 2009 Share Posted May 27, 2009 If I understand correctly, the way your testing them is by holding them open and then letting the water pour through? Really you need to send them away to be tested at various duty cycles. That way you're actually measuring the response of the injectors as well. One might be opening fractionally slower than the rest, which you'll never be able to see using the method I think you're using. Quote Link to comment Share on other sites More sharing options...
Ryan.G Posted May 27, 2009 Share Posted May 27, 2009 i have 2 walbros, using one directly at the oem fuelpipe and the 2nd walbro got an extra 8mm fuelpipe directly to the other end of my oem fuelline with the injectors. the fuelpressor is an aeromotive and i have 3,2 bar fuel pressure. but the a/f was fine and if you run lean the other pistons get a demage too, not only one as far as i know. the injectors are from sard 800 ccm sidefeed for my uk spec. i tested them with water and open them for 30 sec. my guess is that one of them is not fast enought when they get in high revs and have to open/close very fast. but how can i test it? The AFR you see is a collective from all 6 cylinders so you wont see if one is lean. 6 EGT probes will show you though or a set of det cans Also the way you have the Fuel piping i would get redone as if one pump fails its good bye another engine Quote Link to comment Share on other sites More sharing options...
TLicense Posted May 27, 2009 Share Posted May 27, 2009 (edited) Double post Edited May 27, 2009 by TLicense (see edit history) Quote Link to comment Share on other sites More sharing options...
Spoony Posted May 27, 2009 Author Share Posted May 27, 2009 who can test my injectors? Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted May 27, 2009 Share Posted May 27, 2009 Get some new Siemens or Bosch injectors, I have lost count of how many iffy aftermarket injectors I have flow tested. Why is the coolant like concentrated rust essence? I'd run forged pistons too. Quote Link to comment Share on other sites More sharing options...
Spoony Posted May 27, 2009 Author Share Posted May 27, 2009 we ran out of coolant fluid and took water. had a hole in my water piping line and refilled with normal water every 3 days so you can test them? the bosch or siemens injectors are top feed injectors, i would like to keep my oem fuelline Quote Link to comment Share on other sites More sharing options...
paul mac Posted May 27, 2009 Share Posted May 27, 2009 i would also ditch the twin walbro setup for a single bosch, if one of them is breaking down under load you would not know about it Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted May 27, 2009 Share Posted May 27, 2009 (edited) Swap it out to a top feed and get branded OE injectors. I will PM you the info we just discussed. In tank Bosch Motorsport 044 injection pump and a Bosch Motorsport fuel pressure regualtor would also be my advice. Avoid brightly coloured FPR's from across the Atlantic like the plague Edited May 27, 2009 by Chris Wilson (see edit history) Quote Link to comment Share on other sites More sharing options...
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