clean the oem injectors on my own vs aftermarket new ones? (1995 305) Core($) on an injector??

[95Noobie]

I'm amazed that AC Delco injectors are $225 each or more?? Is there rare metals and a built in computer inside? It looks like a mechanical orifice with 2 electrical posts sticking out? Visually I'm seeing a good spray pattern but not getting good performance at low end of RPMs. Runs good at highway speeds, no falter, sputter or miss.

I'd be interested in taking them out, soaking in cleaner or doing a clean procedure if that is possible with typical hand tools and solvents (soak for a while?) It would seem directly cleaning them with a brush would be more reliable than putting techron or gumout or whatnot in the fuel tank and hope it cleans them over time.

The other option (unless oem is highly recommended by you folks) is to get an aftermarket injector which looks like it would be a reasonable thing in a simple device. Oreilly and autozone have different brand injectors both about $50 each. The interesting thing is they charge a Core charge equal to their value which makes me think the aftermarket ones are simply 'cleaned' originals that are resold maybe?

Anyone know why there would be a core charge on a possibly 30 year old injector and what is done with them from here?

 

[Schurkey]

TBI injectors are not known for plugging. That said, Top Tier fuel and a bottle of Techron Complete Fuel System Cleaner at every oil change has been my procedure for decades.

What is your fuel pressure? How old is your O2 sensor? Have you replaced all the normal "tune-up" parts since you've had "poor power"? Verified initial timing and electronic timing advance? Checked for a plugged catalyst?

Carbureted and TBI 305s are dogs. "Poor power" is built-in. But maybe what you're dealing with is excessive even for a 305.

 

[95Noobie]

Our local gas station advertises to have Top Tier Fuel and we only fill there so it has had 4 tanks of 'top tier'. I have Techron fuel cleaner on order. I get lost in all the 'fuel system cleaners' out there. I had run a bottle of SeaFoam through one of the 4 tanks of gas. Visually the spray pattern looks consistent between both injectors.

Truck came to us with no O2 sensor as dual exhaust installer took out factory CAT (said CAT was not functional) We added 2 smaller high flow CATs mainly so we could add an O2 sensor back in. The O2 sensor took the check engine light off (it was on due to low voltage on O2 sensor circuit which would imply there was no O2 sensor at all in place) But then last weekend light came on again, low voltage at O2 sensor. It was only about a 3 week old sensor but I tried a different brand and installed it last night. Engine light back off and it seems to idle and run a bit better with O2 sensor in place. Still feels doggy in the mid-range. It seems that even though the new cats are 'high flow' that just that little disk of catalyst in the exhaust flow makes the truck act like it has too much back pressure or is still starved for air. Tempted to try to reach into the O2 sensor hole and dislodge the catalyst since it ran better with dual exhaust, no cat.

The other option we have on the bench but not installed yet is a throttle body spacer. I don't read much about these on these forums.

Almost all sensors replaced through this process. Waiting on the spark control module as one of the last ones related to ignition that hasn't been replaced. It was a trip to find a negative pressure EGR valve but that is new as well now. Vacuum line to the EGR is new. New ground on the coolant temp sensor. Last fall prior owner did plugs, wires and distributor cap. I did the coil although one of the mounting studs snapped off in the block. I assume coil can still produce proper zap with only one mounting bolt, I hope at least...

I would like to learn how to check fuel pressure. Not sure if my 1995 has a shrader valve in the fuel rail or I need some other tools to determine this. Fuel filter I changed right after we got the truck.

I don't have a tool to check timing but know someone who can help me there. I bought an ALDL adapter for an Innova scan tool advertised to read OBD1 codes but it will not give me data on fuel trim, timing advance etc. Again, I think the same family member has an old Genesis OTC tool that can get me this data.

So it sounds like injectors are working there is no advantage to cleaning them by removing and scrubbing or soaking so I'll run the cleaner in the fuel.

 

[Sean Buick 76]

Not that I think this is your issue however you should be able to send your injectors to a place to have them cleaned and flow tested.

 

[DerekTheGreat]

No easy way to check fuel pressure on these fossils. You need to crack the fat fuel line going into the TBI and put that adaptor they make for these in place. Don't leave it there unless you upgrade the o-ring(s?) in it.

Getting an old Snap-On MT-2500 would let you see the data from all sensors. I've currently got a lazy O2 sensor, cross counts are never higher than 4. I think they should be higher than 20. However, I couldn't get the thing out of the manifold with my Mickey Mouse propane torch and all the beef my flabby ahss could supply... Anyway, that's TMI and not related to your vehicle. When you changed out all these sensors, did you unplug the battery to reset the computer? Years ago my truck had a 7 cylinder in it. When I finally put an 8 cylinder in it, it ran goofy off the line, hesitated. I figured it would tune itself out eventually, but I ended up resetting the computer. It has run great ever since.

EDIT: Last year I swapped in a rebuilt injector pod assembly like this one here. I'm pretty sure I didn't pay that much. Can't remember if I bought it from that seller either, but there is at least a $50 core return. Even with my bum O2 sensor, my truck does run smoother and picked up a couple tenths in the MPG department. New heated O2 sensor to commence in my truck at some point in the future.

 

[95Noobie]

Derek your post is great and I love to hear about the back story. I ran a VIN report on my fossil and it said the truck was made in a plant in Canada and the engine in Warren (my home state) The MRSP was $19,332 (wowsers seriously 20K back in 1995????) and that the highway MPG should be 19 and city 14-15. That was on the sticker at the time it was sold. Amazing how they can advertise that!

Yes, I'm working on either buying an ALDL cable with USB on the other end and buying software to help me read my own sensors or buy a MT-2500 or see if my brother in law's scanner will do this. I need to know what the sensors are doing and what my fuel mixture is doing.

I just went through effort to allow an O2 sensor to be installed again and it appears the brand new O2 sensor failed based on engine light coming on with low voltage at that O2 sensor. I swapped for a different brand (this is the 3 wire heated sensor) and no I didn't reset the computer but that is a good idea. Just unplug battery for 10 min or so?

I'm fine with swapping injectors (if the non-oem are OK then I have 2 parts store that sell off brand injectors probably rebuilt) but then I will need the gasket that goes under them as well as youtube shows what it looks like after taking old injectors out and usually part of the gasket/seal is left behind.

 

[95Noobie]

I was also moving on in the thought process to how I would know if there is head gasket concern with coolant mixing with oil which could reduce power or create vacuum leak situation. I see a little oil in the dimples on top of the engine next to the driver side valve cover which looks like I can solve with new gasket. Saw a little dot of green fluid by the depression by the coolant sensor and yet I replaced the thermostat, added gasket and no leaks there, hoses no leaks that I can see.

Oil on dipstick looks like oil but maybe slight contamination with coolant would be hard to pick up visually? Some say exhaust smell will be different, no experience sniffing exhaust...

 

[95Noobie]

Derek, the ebay seller you linked above is in Michigan close to me. I asked him if I should clean or replace my injectors or if I should get a whole new 'pod' This was his reply. I understand his concern about alcohol and its effect on seals but I can't imagine paying a dollar more a gallon for recreation gas (no alcohol), wow that would be a pricey proposition!!

sharing the reply here:
===
check your fuel pump pressure with a gauge, you can rent one from autozone or any part store. make sure you're getting minimum 12psi from the pump. if less than 12psi change the fuel pumpAt home injector cleaning is not recommended, don't use injector cleaner in the fuel tank or in the injector as the chemical strips the protective coating from the internal copper coil which results in a short.stay away from 10% ethanol fuel and only run recreational fuel without added ethanol. ethanol is corrosive and overtime deteriorates the rubber fuel lines and other fuel system components.its best to replace the entire injector pod with the regulator

 

[L31MaxExpress]

Derek your post is great and I love to hear about the back story. I ran a VIN report on my fossil and it said the truck was made in a plant in Canada and the engine in Warren (my home state) The MRSP was $19,332 (wowsers seriously 20K back in 1995????) and that the highway MPG should be 19 and city 14-15. That was on the sticker at the time it was sold. Amazing how they can advertise that!

Yes, I'm working on either buying an ALDL cable with USB on the other end and buying software to help me read my own sensors or buy a MT-2500 or see if my brother in law's scanner will do this. I need to know what the sensors are doing and what my fuel mixture is doing.

I just went through effort to allow an O2 sensor to be installed again and it appears the brand new O2 sensor failed based on engine light coming on with low voltage at that O2 sensor. I swapped for a different brand (this is the 3 wire heated sensor) and no I didn't reset the computer but that is a good idea. Just unplug battery for 10 min or so?

I'm fine with swapping injectors (if the non-oem are OK then I have 2 parts store that sell off brand injectors probably rebuilt) but then I will need the gasket that goes under them as well as youtube shows what it looks like after taking old injectors out and usually part of the gasket/seal is left behind.

I had a 1994 G10 with a 305, the MPG numbers for your truck are close to what it delivered real world even with over 250K miles on it. My Q-Jet fed 305 was similar even.

 

[Schurkey]

Our local gas station advertises to have Top Tier Fuel and we only fill there so it has had 4 tanks of 'top tier'. I have Techron fuel cleaner on order... ...Visually the spray pattern looks consistent between both injectors.

Good.

Truck came to us with no O2 sensor as dual exhaust installer took out factory CAT (said CAT was not functional) We added 2 smaller high flow CATs mainly so we could add an O2 sensor back in.

You don't need catalyst(s) to have an upstream O2 sensor. But functioning cats don't hurt anything.

it seems to idle and run a bit better with O2 sensor in place.

I'd expect so.

Still feels doggy in the mid-range. It seems that even though the new cats are 'high flow' that just that little disk of catalyst in the exhaust flow makes the truck act like it has too much back pressure or is still starved for air. Tempted to try to reach into the O2 sensor hole and dislodge the catalyst since it ran better with dual exhaust, no cat.

Unless you've got defective catalysts, or some serious problem with the engine that has destroyed the catalysts, they're not doing any harm. Something else is wrong.

But I wouldn't have expected two cats on that vehicle. I figured only one.

The other option we have on the bench but not installed yet is a throttle body spacer. I don't read much about these on these forums.

Essentially worthless. MAYBE they give some very minor boost in power in the upper RPM range, but they're not going to fix problems.

Almost all sensors replaced through this process.

Properly-functioning original sensors may be better than brand-new low-quality replacements.

Test before replacing.

Waiting on the spark control module as one of the last ones related to ignition that hasn't been replaced.

Again, a GOOD original may be better than a bottom-feeder new replacement.

I would like to learn how to check fuel pressure.

Download the service manual set for your vehicle from the links in the Sticky thread section of the Engine forum.

As said, the TBI has no Schrader valve, you'd need to open the fuel supply plumbing to install a temporary adapter.

I bought an ALDL adapter for an Innova scan tool advertised to read OBD1 codes but it will not give me data on fuel trim, timing advance etc. Again, I think the same family member has an old Genesis OTC tool that can get me this data.

"Code readers" are a total waste of time, money, effort, and enthusiasm. Complete junk.

I've never used an OTC Genysis, but they should be comparable to a Snap-On scan tool--a Solus or Solus Pro, perhaps. Likely better than a '2500 Red Brick.

This was his reply. I understand his concern about alcohol and its effect on seals but I can't imagine paying a dollar more a gallon for recreation gas (no alcohol), wow that would be a pricey proposition!!

sharing the reply here:
===
check your fuel pump pressure with a gauge, you can rent one from autozone or any part store. make sure you're getting minimum 12psi from the pump. if less than 12psi change the fuel pump

Problem is more likely to be the fuel pressure regulator, than the pump.

It could be either--or a partially-blocked fuel filter--but the filter and the regulator would be checked first, before the pump.

At home injector cleaning is not recommended, don't use injector cleaner in the fuel tank or in the injector as the chemical strips the protective coating from the internal copper coil which results in a short.

No problem with Techron, or the detergents blended-into Top Tier fuel.

stay away from 10% ethanol fuel and only run recreational fuel without added ethanol. ethanol is corrosive and overtime deteriorates the rubber fuel lines and other fuel system components.

GM themselves say 10% ethanol is no problem at all. 5% Methanol is also OK, so long as it has a "cosolvent" blended-in. I don't know what a "cosolvent" is, and it doesn't matter since there's no Methanol-added gasoline for sale around here, and hasn't been since about 1980.

its best to replace the entire injector pod with the regulator

Translation: I make more profit selling the entire injector pod, than selling a regulator spring and diaphragm kit, plus a bottle of Techron.