Another modded 951 not starting

[Flitzr951]

UPDATE: I went through all of my vacuum connections and made sure everything was properly connected. It still refuses to hold a steady idle and dies off 2-3 seconds after firing up (and it fires up immediately once the key is turned) For the 2-3 seconds the engine is running it sounds like a million bucks. It was not starting at all with the 55lb injectors, so my stock ones are still installed. Could the fact that my chips are set up for 55lb injectors be the reason why it won't run? My TPS seems to be dialed in correctly as well.

About my 55lb injectors, what do I need to do in order to get them installed properly? Someone mentioned testing them across the two pins...with what? Please excuse my lack of understanding, I've never really dealt with the electronic side of the car and I have no previous experience with electronics. So if anyone knows exactly what I need to test, how to do it and what to use, I would really appreciate the help. Thanks

[blown 944]

Check the OHM resistance across the 2 pins on your 55# injectors. Any decent multi meter will have this function.

You will want to make sure they are not the high impedance injectors 16 ohm draw. They should be either 2.4 or 2.6 or 2.8. If they are not you need to get the low impedance injectors and as some have said you will need the ballast resistors, however I have been able to run 2.8 injectors on a 5 ohm system w/o them.

Yes it will absolutely die if your chips are set for 55# injectors, it is running totally lean. You could try to run the fuel pressure up to around 60 psi to see if it will sort out temporarily but don't boost it.

You will need to either re install stock chips or get your injectors figured out.

I personally would check the injectors first and if they are the high impedanc eI think you will have found your problem. If they are the low imp then try the balast resistors.

If all of that doesn't work try stock chips and injectors to make sure you can get any other bugs sorted.

[Flitzr951]

Thanks for the gouge, I'll check that stuff out ASAP.

[bscpanther]

Assuming you got your injectors from LR just like everything else you have they are 2.2 ohms, low impediance.

[Flitzr951]

Originally Posted by bscpanther

Assuming you got your injectors from LR just like everything else you have they are 2.2 ohms, low impediance.

I actually bought them from someone on rennlist, so I need to double check them. He said he ran them without any electrical modifications but I'm going to start looking into it anyway

[nize]

are you able to monitor your a/f ? what does it show?

[Flitzr951]

I checked my injectors and they registered at 12.8. My A/F gauge shows that I'm incredibly lean (for the few seconds the engine is running). So what do I need to do in order to get my injectors online? I'm guessing I'll have to install resistors but once again, I'm not too savvy on the electronic issues.

[nize]

where did you get these injectors? why not get the correct injectors?

[Flitzr951]

I got them from someone on Rennlist, he claimed he had been using them in his track car. At this point, if there is a workaround for the injectors I have, I need to utilize it. I was able to dump the $$ when I was single but now that I'm married things aren't so simple.

[nize]

i'm running the correct 55lb siemens injectors purchased from marren for around $60/per. i find it amusing that lindsey sells the exact same injectors for double the price, and more surprising that people actually pay that much for them;
http://www.injector.com/

lindsey's ripoff price;
http://tinyurl.com/2g8jqf

here are some related threads for info on the resistors;
http://forums.rennlist.com/rennforums/showthread.php?t=182462

http://forums.rennlist.com/rennforums/showthread.php?t=55851

http://forums.rennlist.com/rennforums/showthread.php?t=52132

personally, i would rather spend the $240 knowing you'll have the right injectors, rather than using resistors to create a hack job.

[Flitzr951]

Wow, I had only seen the $400+ that LR charges...I might be able to swing $240, especially if I can sell my current ones. Thanks for the links, I'll have to see what I can work out.

The chart on that site says I would need 88+lb injectors just to make 400hp...with my mods is there really a need for more than 55?

[blown 944]

Did you ever check the Ohm resistance?

[blown 944]

OOps read too low

[blown 944]

Yep that is your problem

[blown 944]

IMO you can't go with those(current) injectors as they are of a higher restance unless you want to change over to a standalone that can use either driver rating.

Have to pony up unfortunately

[nize]

i don't understand why anyone would want to use the high-impedence siemens injectors for the 951 when the correct low-impedence injectors are available for the same price. what's up with that ?

[blown 944]

I wouln't even think of it myself, it really doesn't make sense. Not to mention that the peak hold are a more accurate style of injector anyway.

Unfortunately, with the strange 5 ohm setup of the DME there can easily be confusion as to which direction is OK to go with resistors.

FYI use low imp injectors with resistors not high (saturated) impedance.

I also think it comes down to price.

[nize]

they are the exact same price. $59. they are also the exact same 55lb flow. one requires resistors, the other is plug-and-play. why anyone would want to pick the more difficult (and expensive since you also have to purchase resistors) solution is what i don't understand.

[nize]

Originally Posted by Flitzr951

Wow, I had only seen the $400+ that LR charges...I might be able to swing $240, especially if I can sell my current ones. Thanks for the links, I'll have to see what I can work out.

The chart on that site says I would need 88+lb injectors just to make 400hp...with my mods is there really a need for more than 55?

don't pay attention to the chart. 55lb is fine for around 350whp.

also, it just occurred to me that whoever you bought the injectors from were probably selling them for the exact same reason you are now. i'm betting those injectors are the hot-potato of the 951 world that keep getting passed around and never used.

[blown 944]

Ii was meaning used. I guess I should be clear.

If you look for used injectors you can find high imp injectors cheap everywhere. Low imp are abit harder too fiind and generally at a higher price.

Anyway I'm glad he was able to get it figured out before hurting anything dramatically