Here goes:

When I bought the truck used with 80K miles it began throwing 2 OBD codes. 0171 and 0174.

Through some trial and error, and plenty of research after failing, I found that the intake gaskets were at fault.

Tore the entire intake system off. Replaced intake to head gaskets, sealed both front and rear, replaced upper plenum with the latest one from GM as well as new gaskets there. Also replaced O-rings from fuel lines to the spider injector as well as the o-rings at the rear of the engine where they mate up. Replaced various attachments for vacuum, etc. Replaced Brake Booster hose and related attachments.

Replaced FPR just because since it wasn't easily gotten to and wanted to avoid any problems when I got it all sealed back up.

Got it all sealed back up and ran like a "raped ape". Was quite happy with the outcome.

Wife drove it from home to Havre, MT and back with no problem, although I have to admit that I noticed a hard start condition when it was there. Still ran great though once started.

Wife then drove it from home towards Layton, UT and in Idaho it started sputtering and died.

She managed to limp it to Layton by keeping the fuel tank as full as possible so I was thinking it may have been fuel pump related.

Nope. While in Layton, I had her take it to a mechanic there and have it looked at.

They said FPR is bad (even after I told them that it was a brand new unit and that the injector assembly is the updated one that got rid of the poppets; I used a Standard Motor Parts PR203T).

Also found problems with the steering (unrelated), and cooling system (hole in radiator).

So my questions are these:

1. How likely is the Standard Motor Parts PR203T to have gone out? Are they junky or is it just my bad luck? Should I use a different brand?

2. Could there be another problem with the updated spider that was installed prior to me buying the vehicle? Thinking of replacing the onboard unit with the Standard Motor Parts FJ503 unit. Again, different brand suggested? Reviews on the SMP FJ503 unit are pretty good.

2A. Related Spider question. Is there a tool to remove the new and improved upgraded fuel injectors? Or am I just going to have to get fugly with them to remove if necessary?

3. Also thinking of tearing out the stock radiator and replacing with an aluminum 3-row unit and electric fans. Seems like a good idea but that's just me. I like the idea of more coolant to keep the hooptie cool as well as improving my fuel mileage by removing the belt drive fan setup.

Suggestions? I'm open to ideas.

 

Is the vehicle home and with you - or is your wife still on the road with it?

 

It's back home. Went down to Layton again last week and dragged it back to North Dakota.

Currently in my driveway on ramps, looking real sad.

 

Wow! That's quite a distance - a 1000 mile tow. I'm assuming you have a 96 or newer Blazer.

Why don't we confirm or deny a problem with the fuel pump and/or fuel pressure regulator. I'm betting that the fuel pressure regulator is OK unless it was damaged by the guy that looked at your Blazer in Utah.

To do this you dead end the fuel pump at the fuel filter. With the pump dead-ended it should be at it's max possible pressure. You can find the procedure and specs in the sticky at the top of the 2nd gen forum. 80-90psi IIRC. It should also hold pressure for a certain time after you turn the key off. If you have not checked the fuel pump dead-ended this way - then you cannot say anything about the pressure regulator being good or bad.

Once you have verified the fuel pump will go to plenty of pressure and that the check valve in the fuel pump works - then put the fuel pressure gauge on the Schrader valve on the top of the engine. Turn the key on with engine off. Pressure should read 58-62 psi and should stop bleeding down for a considerable time after the pump has shut off. I know sticky has 60psi at a minimum listed, but it simply isn't what is seen in the field with the upgraded injector spiders. Mine is 58psi and runs great. It's not so important with the upgraded injectors to be above a specific psi. Before the injectors had to reach a certain pressure before delivery. Now they don't, so a couple PSI makes very little difference in fuel delivery and the PCM compensates anyway for minor differences.

p.s. most auto parts stores have good loaner fuel pressure gauges (with deposit).

DO NOT under any circumstance block the return line from the spider and try to check the fuel pump max pressure this way. 80-90 psi is a good way to blow the fuel pressure regulator. Hope the guy that looked at it in Idaho knew this.

Good luck and best wishes for a successful repair!

 

Thanks for that info. Yes. It's a 2004.

I've actually thought about buying a pressure gauge. This is the nudge to do it. Will check that and advise.

Also, the tow sounds worse than it was. I was working out of Great Falls, MT and rented a trailer for a couple days, drove down, loaded it, and came back on day 2. The 2nd part of the tow I used a dolly one way from Great Falls to Drake, ND. For that, I dropped the drive shaft and lifted the front off the ground. No muss, no fuss. Didn't trust leaving the transfer case in neutral for the trip. My luck, something would have burned up.

 

Managed to get out to the garage today and start working. Hooked up the pressure gauge to the schrader near the distributor and fired it up. Just above 50 pounds and fluctuating by +- 2 psi. Nothing to get into a twist about but the pressure doesn't seem high enough and isn't if I read the sticky correctly.

Shut the engine down and looked again at the gauge, absolute 0. No drain time, nothing. Definitely a problem. Will have to get the parts to check at the filter for leakdown.

Would love to say FPR for sure but I'm not totally convinced. I'm not sure about the pump even though it's a new unit as well.

Will advise.

 

Pressure spec is for key on engine off when the key is first turned on (pressure is higher without any engine vacuum) However the immediate leak down indicates further problems. You're on the right track - please proceed as you described.

 

Ok, FINALLY. Got my other work done and now locating the fuel issues. Hooked up a Fuel Pressure Tester to the fuel filter. KOEO and the pressure shot up to 70 PSI plus. When the relay kicked it off, I'll be danged but the damn pressure dropped to zero within about 3-5 seconds. Indicating bad fuel pump. DANGIT!!!!

All that said, I still can't confirm issues with the Fuel Pressure Regulator until I get the pump issues straightened out.

As for the final question in my original post, I've completed the radiator replacement and conversion to electric fans. Can't wait to get the fuel problems taken care of to see what the conversion does for power and mileage. I'll complete a second post detailing the difficulties and things I had to do, along with pics.

 

Glad you are figuring out your problems. Keep us posted.

 

It was a bit of a struggle but got the pump replaced. For the most part the pump has taken care of the major driveability problems.

I've been driving it to and from work for some time now and it only occasionally exhibits any issues when at idle. It occasionally drops to about 500 RPM.

So I suspect that the pressure regulator is still causing issues. I'll be waiting until Spring or Summer to replace it since the vehicle is running fine.

Also, another thing is that I am putting together an almost complete description of what I did to replace the cooling system in my vehicle. Parts list and where I got them, along with some detailed descriptions of how I did things.

Where possible, I will try to give pictures as well.