88 Fires right up then dies a few minutes later

[Art5]

1988 Bronco 302/C6/4X4
Just pulled it out of storage yesterday, been in for less than a year, and after changing the oil and putting in some dry gas and about 5 gallons of fresh gas, I cranked it over and it fired up immediately. Ran at high idle for a few minutes, then as soon as the rpms dropped down it died. Started it back up same thing happened but in a shorter time. Every time I start it same problem. What could be going on with my truck?
 

 

[Rons beast]

Hey Art,

Sounds like a fuel issue.  Probably ethanol deposits are blocking fuel ports.  You could try keeping the engine running at a fast idle longer.  If you have added fuel conditioning agents that will dissolve deposits it could help the problem.

If not a complete fuel system cleaning is the next step.

Good Luck

 

[Art5]

What if I told you I've already replaced all the fuel system components in the last year? Fuel pump, fuel filter, fuel pressure regulator, and all fuel injectors.

 

[miesk5]

yo Art,

If it is EFI,

Try a Self Test for Diagnostic Trouble Codes (DTC)s by my pal, BroncoJoe19

http://broncozone.com/topic/14269-code-reader/?pid=74587&mode=threaded

A helper is good to assist in reading Codes; best is to take a cell fone vid and replay it.

Some basics;

Visual Check

Battery is fully charged & clamps, wire strands and ground points are clean

Inspect the air filter and inlet ducting.

Check all engine AND HVAC (under hood & in /under dash) Vacuum hoses for damage, leaks, cracks, blockage, proper routing, etc.

See my Vacuum Leak Test @ http://broncozone.com/topic/23994-90-58l-getting-continuous-code-33-and-running-code-44/

POST #20

Vacuum Gauge Readings, Interpretation

http://www.diesel-dave.com/vehic/manual/stj/stj30013.htm

The vacuum gauge should read between -51 and -74 kPa (15 and 22 in-Hg) depending upon the engine condition and the altitude at which the test is performed. SUBTRACT 5.5 kPa FOR EVERY 500 METERS ABOVE SEA LEVEL. SUBTRACT ONE INCH FROM THE SPECIFIED READING FOR EVERY 1,000 FEET OF ELEVATION ABOVE SEA LEVEL.

The reading should be quite steady

Dou have or can borrow from friend or w/refundable deposit @ local parts store?

 

[Rons beast]

Ethanol damage can occur in a matter of months or even weeks depending on the humidity of the area.

 

[Art5]

Well I think you're on to something. Seems like a fuel issue but possibly not related to the fuel system components, maybe bad gas?

 

[Art5]

the only code was 42

 

[miesk5]

yo,

42 is

KOEO HEGO sensor circuit indicates system rich (right side).

KOER No HEGO switching detected always rich (right side).

DTC 41, 42, 91, 92, 136, 137,139, 144, 171, 172, 175, 176, 177 & some Possible Causes for Rich & Lean HEGO; "...The engine temperature must be greater than 50°F (10°C) to pass the KOEO Self-Test and greater than 180°F (82°C) to pass the KOER Self-Test. To accomplish this, the engine should be at normal operating temperature.."

DTC 42 O2 sensor voltage was stuck high for too long. (Rich).; "...Bad O2, or it's connector/wiring; bad MAP sensor; Bad fuel pressure regulator, pull vac hose off, any gas in it or gas aroma means it's bad;

Possible Causes:

DTC 41, 42, 85 OR THREE DIGIT CODES 171, 172, 173, 179, 181, 182, 183 & 565 are received, Check for proper HEGO Ground; in Catalytic Converter Diagnosis TSB 91-12-11 for 86-91 Bronco, F Series, & Econoline

by Steve http://www.supermotors.net/registry/media/747751

 

[Art5]

this was koer and engine was not at normal operating temp since truck would only run for a minute or so then die

 

[Rons beast]

If there is not some other underlying problem, Fuel pressure reg. ETC. as M5 mentioned, then the o2 are reading a rich mixture and cutting dwell time to the injectors to lean the engine out, ( because it THINKS the mixture is rich) in reality the mixture has gone too lean and the truck stalls.

Either there is fuel getting in the engine from a unmetered source. or the OS or related wiring is a problem.

Good Luck.  Keep us posted.