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I just bought a 92 Bronco with a 5.0, it has 200000 miles and a SD ignition. It has an MSD cap and rotor with Ford Racing plug wires. I have put new Motorcraft plugs with a .045 gap. I have checked the timing and reset it to 12 BTDC. The detonation has gotten better since i moved the timing back from 30 degrees, but it still happens at times also when under a constant rpm the engine surges. it was bad enough to not complete an emissions test. Any help would be great. I hate to just keep replacing parts. Has anyone seen this problem before.

I plan on putting a 5 speed in and MAF as soon as i can find all the parts, if anyone has any leads on parts in GA or the surrounding area please let me know.
 

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So i got in my Bronco this morning started going up the hill and it was pinging and i had to almost have the pedal to the floor to make it up the hill. :cry I am going to try and pull the codes on it tonight but does anyone have an idea what could be causing it. Like i said before it was running pretty good at 30 degrees advance but doing the tuneup i put it to 10 and now it is running horrible. it is my only other vehicle besides my wifes car. I was going to replace the TPS and MAP sensors just for peace of mind, but i hate to shotgun the troubleshooting.
 

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yo CD,
Spark Plug Wire; Routing TSBs -> Routing for 5.0
Diagrams for 5.0, 87-93; The firing order for 1987-1993 5.0Ls is 1-5-4-2-6-3-7-8. If #7 and #8, or #2 and #4 spark plug wires are routed next to each other at the separation bracket, an induction crossfire condition can occur
by Tank92 (Tank) at http://www.supermotors.net/clubs/superford/registry/5180/32495

do the Code test; here is a Self Test for Diagnostic Trouble Codes (DTC)s by my pal, BroncoJoe19

The engine temperature must be greater than 50° F for the Key On Engine Off (KOEO) Self-Test and greater than 180° F for the Key On Engine Running (KOER) Self-Test.
Run it around to heat the engine up and shift thru all gears incl Reverse. Then turn off all accessories/lights, etc.

Make sure A/C is off and transmission is in Park (automatic) or in Neutral for a Manual & release clutch.

Do Key On Engine Off (KOEO) portion first.

Look Codes up in my broncolinks.com site using the new Search function.

And Post em here according to:
KOEO
&
KOER

Setting the timing by Ryan M at http://oldfuelinjection.com/?p=71
 

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Sounds lean - fuel pressure, fuel volume, filter condition? I'd check that stuff - your codes may put you in the ballpark anyway. You could narrow the gap on your plugs halfway between where you are and what is - so maybe 0.04. If the plugs are gapped like that and they are the wrong heat range you *could* end up with detonation problems so maybe check that your plugs are right for your truck. Vaccuum leak is another possibilit - I think i read that 334 is EGR? And 634 is transmission related and I've got no idea - my guess is that has nothing to do with your problem unless it's somehow tied to a vaccuum line but I'm really not sure. I'm sure someone else will chime in. the 334 code could be causing a vaccuum leak but I'm a bit suprised it would run that poorly....I'm sure someone else can help you more than I can!
 

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and you could buy some higher octane fuel, once its close to empty. see if that helps. alsoyou are pulling the spout connector when timing it correct.?
 

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I had a similar issue with my 94 w/ 351. it was a long drawn out process from hell troubleshooting it til i finally found out that my distributor shaft was magnetized; causing my pip sensor to go haywire. this, in turn, caused horrible ping and an engine "shake". You might stick a non-magnetized screwdriver to your dizzy shaft and see if there's a magnetic "pull". It's prolly not it, but if it is--it'll save you money and time.
 

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So the fuel pressure at idle is 35 psi, fuel filter has less than 100 miles. I put a vacuum on the egr and it moved freely, replacing the solenoid on top of it and the egr controller. The Map sensor and the Aircharge temp sensor. The truck sat for some time, I got it from a college student who only used it to go to the grocery store. Going through everything while i'm at it.
 

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Don't just check pressure, check volume - you can have good pressure and not enough volume. Try to have a listen to your injectors too - clean injectors are noisy, they make a clatter almost like little diesel engines - use a screwdriver on the LIM or if a piece of vacuum line if you've got it to have a listen. I doubt that's it but it's a quick check - presumably, a bad injector would have thrown a code. Don't bother doing anything else until you replace that EGR solenoid though - I agree that an EGR stuck open could cause pinging, I'm just surprised it would affect the drivability so much - but it's definitely the most likely culprit at the moment.
 

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yo,


DTC 334 EGR (EVP) closed valve voltage higher than expected; "...Failed sensor, & as by rla2005 (Randy) wrote; carbon between EGR pintle valve and seat holding the valve off its seat. Remove the EGR valve and clean it with carbon remover. Prior to re-installing see if you can blow air through the flange side of the EGR by mouth. the egr is not closing properly which can cause detonation. remove the egr and clean off any carbon built up on it with carb cleaner and a brush if necessary. The EGR Valve Position (EVP) Sensor used exclusively by Ford, can be the cause of driveability problems without ever setting any trouble codes. The relationship between the EVP sensor and the EGR valve is important to understand. Either one being out of spec can cause similar symptoms. Understanding this relationship will help you to diagnose uncoded driveability problems like stumbles, hesitations, rough idles and stalling..." read more
Source: by rla2005 (Randy) & miesk5 at http://fullsizebronco.com/forum/showthread.php?p=2135529&posted=1#post2135529

DTC 334: CHECK FOR DTC 558 in Key On Engine Off (KOEO) or Engine Running (KOER) Self-Test indicates the EGR valve and/or EGR Valve Position (EVP) sensor may not be fully seated in the closed position. The EVP sensor voltage is greater than the closed limit voltage of 0.67 volt. "...Breakout box pin numbers correspond directly to EEC connector pin numbers. Because of the preload on the installed EVP sensor, it is difficult to determine whether the EGR valve is seated or the EVP sensor is in contact with the EGR valve stem. Possible causes: Poor continuity in EVP sensor harness. Non-seated EGR valve. Damaged EGR valve. Damaged EVP sensor. Damaged EVR solenoid. Damaged Powertrain Control Module (PCM). Key off; Substitute EEC for "breakout box"..." read more
Source: by F..d via miesk5 at http://fullsizebronco.com/forum/showthread.php?t=200896B

DTC 67 & DTC 634; Manual Lever Position/Transmission Range (MLP/TR) Sensor Pin-Point Test in 92-96; from F..rd EVTM; "...Check the resistance of the MLPS: The resistance of the MLPS (pins 30 and 46).." read more

DTC 67 & DTC 634; E4OD Nagging Neutral Nonsense & Pinpoint Test, Manual Lever Position (MLPS) also called Transmission Range (TR) Sensor. "...One of the most-difficult problems to diagnose on a Ford car or truck is a sudden neutral condition while the vehicle is cruising in 4th gear. Now this can have a number of causes, depending on which transmission is in the car or truck, but the cause we are going to discuss here is that #(~! *&A% Manual Lever Position Sensor – that’s right, the old MLPS. This sensor is responsible for more malfunctions than any other sensor in the system, and the kicker is that it seldom stores a code 67 or 634. Actually there is a standing joke in our industry that says, “You got a problem with a Ford, change the MLPS; it fixes everything,” which ain’t that funny because it’s not that far from the truth. Some of the problems the MLPS can cause are wrong gear starts, TCC hunting, no 4th gear, engine stalling, high or erratic line pressure and the problem that this article is about – a sudden neutral condition. Whether the MLPS is attached to an E4OD, AXODE, AODE or CD4E, the operating characteristics are the same. What that means is the MLPS is classified as a step-down resistor. The MLPS is supplied 5 volts from the computer as a reference voltage, and as the shift lever is moved from park toward manual low, the voltage in each gear-shift position will decrease as shown in Figure 1. The MLPS also can be checked for correct resistance, also shown in Figure 1. This way, if the resistance checked good on the bench but the voltage does not check good in the vehicle, you know there must be a wiring or ground problem. I know what you are thinking: You replace the MLPS on every job you do, so why should you check the resistance on a new part? Well, that’s fine, but one thing has become very clear lately: NEW DOES NOT MEAN GOOD! Now, let’s get to the meat of the problem. As you can see in Figure 1, the voltage in the drive/overdrive position can be 1.88 to 2.30 volts. The O.D. Cancel button, on those vehicles equipped with one, has no effect on the voltage seen in the drive position, nor does it matter whether the vehicle has a gas or diesel engine. This would be the voltage seen in the D or D position if it were available on the scan-tool screen in the data mode. Unfortunately, this information is not always available, and this “glitch” may occur faster than the scan-tool’s update capability so the voltage jump would be missed. Therefore, a digital multimeter must be used to monitor this voltage. This is of the utmost importance in diagnosing the sudden-neutral condition. This voltage should be monitored when the neutral condition occurs by placing the multimeter’s positive lead to computer terminal 30 if it is an EEC-IV system, as illustrated in Figure 2, or to terminal 64 if it is an EEC-V system. This wire is light blue/yellow on all applications except vehicles with the CD4E. On these the signal wire is red/black. Now, here is where this gets a little involved. The negative lead of the multimeter should be placed at the MLPS signal-return ground terminal at the MLPS. The reason is that the ground circuit for the MLPS can be shared by as many as FIVE other sensors, as seen in the wiring diagram in Figure 2. This means that there are factory splices in this ground circuit. If you check this ground at computer terminal 46 for the EEC- IV or computer terminal 91 for the EEC-V, the ground may check good but could be bad at the MLPS if there is a problem on the MLPS side of the splice, as also can be seen in the wiring diagram in Figure 2. The ground-circuit wire for 1989-90 F- and E-series trucks is black/white; all other vehicles use a gray/red ground wire except for CD4E applications, on which the ground wire is black/blue. Once the multimeter is connected to these circuits, as seen in Figure 3, place the meter where it can be seen while driving. When the transmission suddenly neutrals, be sure to have someone observe the multimeter, or use the meter’s MIN/MAX feature to record the highest and lowest voltage readings that occurred in the circuit. If the voltage jumps toward 3 volts as shown in Figure 3, and at that very moment the transmission neutrals, either the MLPS is faulty or the MLPS ground circuit is poor. Under normal conditions, this voltage reading SHOULD NOT CHANGE! When the voltage jumps toward 3 volts, this indicates a neutral-shift- lever position to the processor. This confuses the computer’s logic system, and therefore the computer is unable to fire the shift solenoids correctly (I think), and – BAM – you have a sudden-neutral condition. Why does the voltage jump because of a poor ground? The poorer the ground, the higher the resistance will be in that ground circuit. The higher resistance will cause the voltage in the overdrive or drive position to rise toward the 5-volt reference voltage, much like putting a bend in a garden hose would raise the pressure in the hose behind the bend. Ground- circuit integrity can be verified by placing the positive multimeter lead to the MLPS ground terminal at the MLPS and the negative multimeter lead to the negative battery post, as seen in Figure 4. With the multimeter set to DC volts and the engine running, the maximum voltage should be 0.1 volt. If more than 0.1 volt is seen on this ground circuit, it is NOT a good ground. In order to correct this condition, cut the ground wire close to the MLPS, attach it to a known good ground and recheck as previously described. Two things must be remembered here. One is that the return electricity will seek the path of least resistance. This path MUST be the ground circuit, NOT your multimeter. That’s why you should see a maximum of 0.1 volt on any 5-volt-reference ground circuit; 0.3 is acceptable on a 12-volt-reference voltage supply. The second thing to remember is that most electrical- fault phone calls I receive on the ATSG helpline are ground-related problems, so be sure to use the voltage-drop method of checking grounds as described. It may help to prevent you from falling into this trap..." See Diagrams & instructions
Source: by Pete L at http://www.transonline.com/transdigest/magazines/1998-10/Shift Pointers/index.html
 

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So i figured i would give an update on the issue. Thought that the harmonic balancer might have spun, needless to say that was not the issue. I dug deeper and found that the guy had put the cam timing gear on backwards ground the bolt heads down and wore a groove in the gear. I will try to post some pics tonight when I get home. Looks like i will be building a 351 to put in it's place when this engine finally dies.
 

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WOW
 
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