more info on hestitation, powerloss. did it again today Options

[mk7celica]

Well I had another thread on this problem and I thought it was my spark plug wires that I just installed because the problem seemed to start right after i did the plug install. Well I thought it was the walbro fuel pump because it gets so loud and the sound keeps changing and getting higher. The problem seemed to be gone until today I floored it to get over and sure enough the hesitation and power loss & jerking began again. Then I drove it for 3-5 seconds and it stopped. So I poped the hood and looked at the engine, wires plugs sensor connections ect, and I found that if I touch my a/c idle control valve and the vacum lines that go to it the car starts to die and then kills. I am thinking when I give wot the engine moves and this is picking up the ac idle valve and the vacum lines like when I touched them with my hand and it killed the same is happening when the engine moves. Any one know about a a/c idle control valve and the vacum lines. Mine has a air sound coming out of it. Its the bolt and spring with vacum lines going to it, not sure the correct name of it

[95st-celica]

check all your vac lines really good...even one vac line disconected or a line cut or a hole somewhere would caus that to happen...is your AC on when you are driving? make sure everything is off, take it for a ride...then turn everything on AC and put it on high and compare the difference between the 2. if your not to worried about ac pull the idle up valve off, cap your vac lines and that will probably solve your problem...if you want to keep the AC..which i would want, then double and tripe check all the lines...EVERYWHERE...behind the block, make sure all the conectors are connected and see if you can find anything...you have to do more then just look at your plugs and wires....check it out really good, and any line that might look like it has some wear to it....buy some stock in vac. hoses and lines and you should be good to go

This post has been edited by 95st-celica: May 7, 2009 - 12:10 AM

[mk7celica]

The a/c is off when I do this I only use the a/c once in a while or long trips. Is it suppose the have a loud air sound coming out of the valve? And When I turn the ac on when I am driving normal the engine seems to lose power but i guess its normal when a ac is on. Do I need hose clamps on all the vacum lines on the ac valve? there are none on it and the valve is rusty bad

[95st-celica]

yea its normal for the engine to die a little bit...but nothing crazy..pull the lines off and sand the rust and **** off so you have a clean neck to connect the hose....then go buy some hose clamps...you defentially need clamps for all the vac lines....see if they have the kind where you press with a pair of pliers rather then the screw kind...its a little more clean and there easier...put everything back on with good conections and see if that makes a difference

[mk7celica]

Have all new vacum lines and it is doing it still. One thing is if its in nuetral and you rev it it revs fine all the way up the rpms to 7000. It only breaks up driving and it doing it bad now. It revs fine in nuetral and breaks up when moving. Can it be boost related will the engine hesitate if boost stops flowing? Or is interupted in some way?

[95st-celica]

are you sure your not hitting fuel cut? are you throwing any check engine lights? and if so what are they? you have to make sure the car is running, then put a paper clip or a wire or something in your diagnostic box, i believe its in E1 and T1 then go around the car a watch the flashing check engine light to see how many times its blinking. are you running 93 octane in it? what oil are you using? is the oil full? are there any bare wires showing or touching anything? are all your grounds connected to a good metal surface on the body or frame? all sensors are pluged in? how many pounds of boost are you on?

[mk7celica]

are you sure your not hitting fuel cut? are you throwing any check engine lights? and if so what are they? you have to make sure the car is running, then put a paper clip or a wire or something in your diagnostic box, i believe its in E1 and T1 then go around the car a watch the flashing check engine light to see how many times its blinking. are you running 93 octane in it? what oil are you using? is the oil full? are there any bare wires showing or touching anything? are all your grounds connected to a good metal surface on the body or frame? all sensors are pluged in? how many pounds of boost are you on?

Ok oil is 1/4 quart low, will change oil this weekend. I run 93 always have. No codes as of last week but I will check again. Oil is synthetic by quakerstate. No wires that I can see. My oxygen sensor wire is bare on the end but its not close to anything. I am on stock boost but with a crappy mbc from ebay. I was thinking it is bad.