mblaney
Full Access Member
I check my injectors this past weekend; it was a fun experience and I learned a lot. I have videos of two tests that demonstrate the fancy gauge calibrator that I borrowed from work.
I installed new Delphi BB injectors late last fall and I didn’t do a pop test at that time. I wasn’t overly concerned about that because I had intended to check them after a few miles were put on them (and I didn’t have the fittings necessary at that time). The engine had a very noticeable shake at idle and had what I describe as a ‘gallop’. After adjusting the injectors the idle is now very smooth. I have about 6000km on the new injectors.
Of the eight injectors, three were acceptable – popping between 1850 and 1866. The worst one was 1650 psi; on average the bad ones were low by approximately 120psi.
Here is a list of observations and lessons learned.
1. Having the digital gauge with peak hold was very helpful and made it easy to see how repeatable an injector was. I quickly developed a feel for how consistent an injector was – some were noticeably better and popped +/- 5 psi while others were cruder with +/-10 and the odd time one would ‘misfire’ 20 high.
2. After shimming, it takes a few cycles (injections) for the injector to settle down. I would fire three or four times before taking measurements.
3. The shims from the Stanadyne (OE) injectors do not fit the Delphi! The OD of the OE are 0.308, Delphi takes OD 0.300. I had to turn down the OD on a stack of shims to be able to use them.
4. The OE injectors use very few shims; there are two 0.062 spacers and maybe one shim – usually 0.004. This means that the OE injectors are not a good source of shims for the new ones. I had to grind down several of the 0.062” to make 0.047” shims.
5. The Delphi injectors are not shimmed IMO. They have two spacers 0.022 and no additional shims. I don’t think these are popped at the factory – they probably use a dimensional measurement of the spring + spacer height and call it a day. Of the five that I adjusted they had exactly the same spacers installed. The lesson is what is always repeated here: “do not install untested injectors, even if they are new”.
I thought I would have fun and video this. Hopefully this post is helpful to others.
http://www.youtube.com/watch?v=fWOQyHFpzDA&feature=youtu.be
I installed new Delphi BB injectors late last fall and I didn’t do a pop test at that time. I wasn’t overly concerned about that because I had intended to check them after a few miles were put on them (and I didn’t have the fittings necessary at that time). The engine had a very noticeable shake at idle and had what I describe as a ‘gallop’. After adjusting the injectors the idle is now very smooth. I have about 6000km on the new injectors.
Of the eight injectors, three were acceptable – popping between 1850 and 1866. The worst one was 1650 psi; on average the bad ones were low by approximately 120psi.
Here is a list of observations and lessons learned.
1. Having the digital gauge with peak hold was very helpful and made it easy to see how repeatable an injector was. I quickly developed a feel for how consistent an injector was – some were noticeably better and popped +/- 5 psi while others were cruder with +/-10 and the odd time one would ‘misfire’ 20 high.
2. After shimming, it takes a few cycles (injections) for the injector to settle down. I would fire three or four times before taking measurements.
3. The shims from the Stanadyne (OE) injectors do not fit the Delphi! The OD of the OE are 0.308, Delphi takes OD 0.300. I had to turn down the OD on a stack of shims to be able to use them.
4. The OE injectors use very few shims; there are two 0.062 spacers and maybe one shim – usually 0.004. This means that the OE injectors are not a good source of shims for the new ones. I had to grind down several of the 0.062” to make 0.047” shims.
5. The Delphi injectors are not shimmed IMO. They have two spacers 0.022 and no additional shims. I don’t think these are popped at the factory – they probably use a dimensional measurement of the spring + spacer height and call it a day. Of the five that I adjusted they had exactly the same spacers installed. The lesson is what is always repeated here: “do not install untested injectors, even if they are new”.
I thought I would have fun and video this. Hopefully this post is helpful to others.
http://www.youtube.com/watch?v=fWOQyHFpzDA&feature=youtu.be
Last edited:
I'll pop test everyone's inj here locally and mail it badk 
:drool
