Injector questions

[brsvo]

My car (86 SVO FMIC LA3 Turned intake-knock sensor disconected) is breaking up under laod. I have done all the usual checks including repacing Cap,rotor,wires,plugs,tfi (tested the TFI and it tested good-replaced it anyway) and coil. The fuel pressure is good and rises with boost. TPS is set correct and timing is 10' advanced with spout out. Cam timing checks good using string method. I have a cheap narrow band AFR guage and it doesn't seem weird. I ran codes and got nothing but LA3 normal codes. I borrowed a chassy ear diagnostic device and put it on my injectors. The manual said they should sound like metal on metal and ring clear. One does but the other 3 are all different tones? Would you suggest cleaning/replacing? If cleaning how? Any help will be worth a beer somewhere down the road. Really frustrated right now, Bruce

[SVO86]

I sent mine out to this place big difference after I reinstalled them they even give a print out of flow test before and after. http://injector-rehab.com/index.htm

[Patrick]

I sent mine out to this place big difference after I reinstalled them they even give a print out of flow test before and after. http://injector-rehab.com/index.htm

Please do a review on them if you like their work.

[Jay4hand]

Can you give a more detailed description of your problem? I'm a pretty decent tech.
Also if you want to do a really good job of cleaning your injectors, take an injector harness from a junkyard and hook it up to a 9v battery and spray fuel system cleaner in it, the battery keeps the injector open. You can also watch the spray pattern. What I use is a large syringe (the kind you used for baby medicine works best) with the plunger and needle removed. Plug the fuel line side of the injector into the plunger side of the syringe. Then I use a decent straw and nozzle on the needle side with the cleaner.

[Bob Holmes]

Usually I look to a bad fuel pump for this symptom, however you state that you have rising rate fuel pressure under boost. Can I ask how you measured it?

Unfortunately, the next thing on the list is valve springs. Are they the original springs?

Can you tell us the conditions under which it "breaks up." I know you say its under load, but could you provide more detail?

[Patrick]

Bruce, new plug wires and plugs may get rid of the bugaboo's. So many times the cheap parts fix the problem.

[SVO86]

Will do Pat! Ill show the report of flow test for
anyone intrested.
Rob

[Robertosvo]

Have a look at all your connections for the front mount intercooler, you may have blown a hose

[Stinger]

What's the plug gap? I've seen far too many people use the plugs right out of the box (.040" or so) or gap to .035" (factory spec) and it cut out under boost. Reduce the gap to .030" if it's more than that currently. There is a good chance it will fix the problem (and if it doesn't, it will prevent one down the road).

[Bob Holmes]

Good point, we had a hell of a time with break-up until we checked the plugs and found broken porcelains. Changed to a colder plug and fixed the problem.

[brsvo]

I have autolite plugs gapped at .029". I have a Prosport elecric fuel pressure gauge on my steering collum. Pat, cap,rotor,plugs and wires was the first thing I did. (been there done that) The car seams to run ok at idle and up to 2000 rpm but if I push at all it acts like the knock sensor is kicking in but I have it disconected so thats not it. I know knock and its not pinging (ask me how I know) it just sounds like a miss. It still makes boost and power but I won't push it because its not right. I checked the IC connections and they are tight. You gave me an idea though! I should disconnect my Tial BOV and see if it changes anything. But I already have the injectors out so I will drop them off after work to get them cleaned localy at Fuel System Inc. Report back in a few days, Bruce

[brsvo]

Well cleaning didn't do anything so I went in search of driveline noises possibly being the culprit. Turned out the DS yoke was toast. I have another tread for my Driveshaft repair which fixed the problem. Weird it sure sounded and felt like a miss but thankfully its working again. Thanks for the inputs, Bruce